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Skin symptoms and physical signs 

Skin symptoms and physical signs
Chapter:
Skin symptoms and physical signs
Author(s):

Huw Llewelyn

, Hock Aun Ang

, Keir Lewis

, and Anees Al-Abdullah

DOI:
10.1093/med/9780199679867.003.0004
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Subscriber: null; date: 21 October 2017

Diagnosis in dermatology

Diagnosis is based on pattern recognition in a far more direct way in dermatology than in other specialties. The diagnosis becomes final with the response of the problem to treatment or by its long-term progress. Biopsy and histology are also used widely, especially when malignancy is suspected or the treatment involves prolonged use of toxic drugs. Identify one aspect of the skin appearance so that it can be used as a diagnostic lead, and scan the pages showing diagnoses linked to that lead to see if you can recognize the remainder of a pattern compatible only with one condition. By seeing many patients, you will learn to ‘recognize’ conditions more readily.

Brown macule

Flat, well-demarcated area of brown skin of any size. Main test is photography to assess change or biopsy usually to exclude malignancy. Initial investigations (other tests in bold below): FBC, digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

  • Flat mole (junctional naevus)

  • (distinguish from malignant melanoma)

  • Suggested by: little variability of brown pigmentation, smooth outline—not irregular, multiple, no symmetry of lesions, not raised, or surrounded by erythema.

  • Confirmed by: no change over weeks to months, benign biopsy appearance.

Freckles and solar lentigines

  • Suggested by: small (<5mm), pale brown, asymmetrical macules, especially on face, red-haired, increased prominence after exposure to sun, asymmetrically distributed.

  • Confirmed by: no change over months to years.

  • Finalized by the predictable outcome of management, e.g. good response to cryotherapy.

Chloasma

  • Suggested by: appearance of large (>5mm) areas of pigmentation during pregnancy.

  • Confirmed by: resolution in months following delivery.

  • Finalized by the predictable outcome of management, e.g. sunscreens, and camouflage cosmetics.

Café-au-lait spot often (esp. if >6 in no. and >5mm diameter) associated with neurofibromatosis

  • Suggested by: one or more light brown, flat, sharply demarcated, evenly pigmented oval macules.

  • Confirmed by: no change over months to years.

  • Pseudo-acanthosis nigricans

  • (benign, no association with malignancy)

  • Suggested by: dark spots on the skin in the flexures, e.g. axillae of obese people, type 2 diabetics, or acromegalics.

  • Confirmed by: no change over months or years. Diagnosis of underlying condition.

  • Finalized by the predictable outcome of management, e.g. treating underlying condition resulting in resolution.

  • Acanthosis nigricans

  • (may be associated with malignancy, diabetes mellitus or malignancy)

  • Suggested by: skin thickening and pigmentation over months or years.

  • Confirmed by: presence of pigmented, velvety, and papillomatous skin lesion of flexures, neck, nipples, and umbilicus.

  • Finalized by the predictable outcome of management, e.g. improvement after weight reduction, and after treating underlying conditions.

Berloque dermatitis

  • Suggested by: red-brown macules on neck after exposure to sunlight.

  • Confirmed by: history of bergamot-containing cosmetics applied to same area.

  • Finalized by the predictable outcome of management, e.g. sunblock and avoidance of exposure to sun.

Plant chemical hyperphotosensitivity

  • Suggested by: red-brown macules on arms, hands, and face (blistering first) after exposure to sunlight.

  • Confirmed by: history of cutting plants (e.g. giant hogweed) without skin covering.

  • Finalized by the predictable outcome of management, e.g. sunblock and avoidance of exposure to sun and exposure to certain plants.

  • Hutchinson’s freckle

  • (with risk of progression to malignant melanoma)

  • Suggested by: large, irregular macule developed from smaller one with variable expansion, regression, or coalescence to form irregular pigmented areas up to 10cm in diameter.

  • Confirmed by: history and appearance and no change over time (biopsy to exclude malignancy if there is change).

  • Peutz–Jegher’s syndrome

  • (with risk of colonic and other neoplasms)

  • Suggested by: small (<5mm) macules on the lips, in the mouth, and around the eyes and nose; also around the anus, hands, and feet. Present since infancy or childhood and fade with age.

  • Confirmed by: presence of polyposis coli on colonoscopy.

  • Finalized by the predictable outcome of management, e.g. colectomy.

Red macule

Flat, well-demarcated area of red skin. Main test is photography to assess change or biopsy, usually to exclude malignancy. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

  • Drug reaction or allergy

  • (e.g. due to penicillins, cephalosporins, anti-epileptics)

  • Suggested by: red macular (or papular) rash up to 2wk after taking drug ± itching, burning, uniform pigmentation, symmetrical, on lower face or trunk ± fever, eosinophilia.

  • Confirmed by: resolution when drug removed and no recurrence if avoided.

  • Finalized by the predictable outcome of management, e.g. emollient, antihistamines, withdrawal of most recently used drugs, e.g. antibiotics.

Viral exanthema from unknown agent

  • Suggested by: red, non-itchy rash with uniform pigmentation. Related systemic symptoms.

  • Confirmed by: appearance, spontaneous resolution.

  • Finalized by the predictable outcome of management, e.g. antipyretic.

Measles

  • Suggested by: red, non-itchy rash with uniform pigmentation. Related systemic symptoms.

  • Confirmed by: appearance, spontaneous resolution, consistent with an incubation period of 10–14 days.

  • Finalized by the predictable outcome of management, e.g. antipyretic.

Rubella (in pregnant mothers complicated by congential malformation)

  • Suggested by: red, non-itchy rash with uniform pigmentation. Related systemic symptoms.

  • Confirmed by: appearance, spontaneous resolution, consistent with an incubation period of 14–21 days.

  • Finalized by the predictable outcome of management, e.g. antipyretic.

Pale macule

Flat, well-demarcated, pale area. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Post-inflammatory hypopigmentation

  • Suggested by: history of preceding red macule.

  • Confirmed by: resolution when drug removed and no recurrence if avoided.

  • Finalized by the predictable outcome of management, e.g. resolution after withdrawal of most recent drugs, especially antibiotics.

Vitiligo

  • Suggested by: FH, non-itchy, white patches of the skin, usually sun-exposed areas, premature greying of hair, and symptoms of other associated autoimmune disorders, e.g. thyroid problems, pernicious anaemia, alopecia areata, and diabetes mellitus.

  • Confirmed by: typical appearance, +ve autoimmune profile, skin biopsy shows absence of melanocytes.

  • Finalized by the predictable outcome of management, e.g. treating underlying conditions, sunscreens, and use of cosmetics. Counselling in depressed patients (because of appearance), topical steroids, psoralen and UVA (PUVA), or depigmentation of normal skin to match affected one.

Pityriasis versicolor

  • Suggested by: history of excessive sweating or immunosupression. Appearance of well-defined, scaly, pale brownish, and uneven patches, usually on upper back and chest.

  • Confirmed by: microscopy, culture, and Wood’s light examination of skin scrapings show presence of Pityrosporum orbiculare.

  • Finalized by the predictable outcome of management, e.g. good response to local application of selenium sulphide or ketoconazole shampoos, and to systemic antifungals, e.g. itraconazole if severe.

Pityriasis alba

  • Suggested by: young age, excessive dry skin, abrasive clothing, stress, and atopy. Skin lesions itchy and more apparent in summer.

  • Confirmed by: presence of superficial, pale, slightly scaly, brown macules with irregular margins on face, neck, arms, and trunk, and the rash quickly becoming red in the sun.

  • Finalized by the predictable outcome of management, e.g. moisturizing creams, topical steroids, and oral antihistamines, e.g. chlorphenamine.

Papules

Raised lesion, <5mm diameter. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Acne

  • Suggested by: young teen, oily skin.

  • Confirmed by: multiple comedones, open (blackhead spots) or closed (whitehead spots), in addition to papules and pustules, cysts, and scarring depending on severity.

  • Finalized by the predictable outcome of management, e.g. response to washing the face gently with a cleanser. Topical and/or systemic treatments for weeks, months, or years.

Scabies

  • Suggested by: severe itching, especially at night ± other members of family affected.

  • Confirmed by: presence of burrows on sides of fingers, wrists, ankles, and nipples. Microscopic examination.

  • Finalized by the predictable outcome of management, e.g. malathion lotion applied on the whole body for 24h, repeated after 2wk and treatment of all close contacts, washing clothes and bedding.

Viral wart

  • Suggested by: history of contacts, use of swimming baths, immunosuppressant.

  • Confirmed by: presence of dome- or flat-topped papules on hand, leg, and face, usually multiple.

  • Finalized by the predictable outcome of management, e.g. topical salicylic acid, cryotherapy, cautery, or curettage if no spontaneous resolution.

Molluscum contagiosum

  • Suggested by: affecting children or young adults, and history of contacts.

  • Confirmed by: dome-shaped, umbilicated papules; if squeezed, produce a cheesy material.

  • Finalized by the predictable outcome of management, e.g. expressing contents with forceps, curettage, or cryotherapy if no spontaneous resolution.

Orf

  • Suggested by: history of contact with sheep, e.g. farmers, vets. Bottle-feeding of a lamb. Presence of affected sheep.

  • Confirmed by: solitary, rapidly growing, red papule, usually on a finger.

  • Finalized by the predictable outcome of management, e.g. if no spontaneous resolution, topical and systemic antibiotics for systemic infections.

Campbell- de-Morgan spots

  • Suggested by: small, bright red non-blanching papules on trunk of elderly or middle-aged people. Can be associated with chemical exposure, pregnancy, and prolactinoma.

  • Confirmed by: no change for months.

  • Finalized by the predictable outcome of management, e.g. if no change over time, excision by cauterization.

Skin tags

  • Suggested by: elderly or middle-aged, often obese.

  • Confirmed by: pedunculated, usually neck, axilla, eyelids.

  • Finalized by the predictable outcome of management, e.g. excision or cryotherapy.

Milia

  • Suggested by: age, usually a child. Mostly on face as small, white papules.

  • Confirmed by: above typical appearance.

  • Finalized by the predictable outcome of management, e.g. spontaneous resolution with no specific treatments.

Insect bite

  • Suggested by: history.

  • Confirmed by: presence of a localized papule or blister, or a generalized allergic reaction. A sting mark in the centre.

  • Finalized by the predictable outcome of management, e.g. if anaphylactic reaction, adrenaline and oxygen; carrying adrenaline auto-injector for future events. For local irritation, ice pack, and antihistamines.

Early seborrhoeic wart

  • Suggested by: patient is elderly or middle-aged. Pigmented, raised spot.

  • Confirmed by: multiple lesions, mostly on trunk and face. Lesions have a ‘stuck-on’ appearance with keratin plugs and well-defined edges.

  • Finalized by the predictable outcome of management, e.g. liquid nitrogen or cryotherapy.

Xanthomata

  • Suggested by: yellowish papules on the hands, tendons, and eyelids.

  • Confirmed by: raised fasting lipids.

  • Finalized by the predictable outcome of management, e.g. treating underlying hyperlipidaemia ± cauterization or excision.

Guttate psoriasis

  • Suggested by: +ve FH. Sudden onset. History of a throat infection.

  • Confirmed by: acute, symmetrical eruption of ‘drop-like’ and slightly scaly lesions on trunk and limbs.

  • Finalized by the predictable outcome of management, e.g. antibiotics for streptococcal infections, topical agents (e.g. emollients), steroids, vitamin D analogues, dithranol. Systemic treatment, e.g. PUVA, methotrexate.

Lichen planus

  • Suggested by: very itchy, polygonal, flat-topped, violaceous papules affecting flexor surfaces, palms, soles, membrane, and genitalia. Recurrent and can affect mucous membranes like inside of mouth.

  • Confirmed by: typical appearance of the rash. If necessary, skin biopsy with the typical telltale appearance under the microscope.

  • Finalized by the predictable outcome of management, e.g. spontaneous resolution, response to topical steroids, oral antihistamines. Mouthwashes for the oral lesions. Systemic oral steroids or PUVA if severe.

Pityriasis lichenoides chronica

  • Suggested by: chronic nature, scattered, small papules on limbs and trunk.

  • Confirmed by: papules topped by a fine, single scale.

  • Finalized by the predictable outcome of management, e.g. antibiotics for associated infections, antihistamines for itching ± local steroids, or tacrolimus ointments, or UV treatment.

Prickly heat

  • Suggested by: history of travel to a high temperature area.

  • Confirmed by: tiny red papules improving when back to colder environment.

  • Finalized by the predictable outcome of management, e.g. cool bathing and avoidance of excessive temperatures.

Keratosis pilaris

  • Suggested by: papule in child or young adults, better during summer, worse in winter.

  • Confirmed by: tiny, follicular, hyperkeratotic, non-itchy papules with erythema on upper arms with a typical gooseflesh or sandpaper appearance.

  • Finalized by the predictable outcome of management, e.g. abrasive pad to smooth skin, exposure to sun; local treatment, high potency steroids, urea, and topical retinoids if severe.

Blue naevus

  • Suggested by: solitary, blue, small papule on the dorsum of the foot or hand.

  • Confirmed by: colour is a shade of blue. Excision and histology.

  • Finalized by the predictable outcome of management, e.g. excisional biopsy.

Basal cell carcinoma

  • Suggested by: history of chronic solar damage, in white-skinned, most commonly face and neck. Nodular, domed-shaped, necrozing in the centre, producing an ulcer with rolled edges.

  • Confirmed by: excision and histology.

  • Finalized by the predictable outcome of management, e.g. cryotherapy, excision, or radiotherapy.

Malignant melanoma

  • Suggested by: FH, fair skin, multiple moles. The mole itself is asymmetrical in shape, has an irregular border, is deep black or two colours and >7mm in diameter.

  • Confirmed by: excision and histology.

  • Finalized by the predictable outcome of management, e.g. excisional biopsy.

Darier’s disease

  • Suggested by: usually teenagers or young adults, other members of the family may be affected, unpleasant smell from patient.

  • Confirmed by: itchy, scaly, waxy, greasy papules, commonly affect the chest.

  • Finalized by the predictable outcome of management, e.g. avoiding sun exposure, heat and humidity. Moisturizers and sunscreens. Tretinoin 0.1% cream under occlusion or a potent topical steroid.

Acanthosis nigricans

  • Suggested by: skin thickening and pigmentation over months or years.

  • Confirmed by: presence of pigmented, velvety, and papillomatous skin lesion of flexures, neck, nipples, and umbilicus, ± underlying disease, e.g. diabetes mellitus, acromegaly and malignancy.

  • Finalized by the predictable outcome of management, e.g. weight reduction and treating underlying conditions.

Pseudoxanthoma elasticum

  • Suggested by: grouped, yellowish papules, mainly affecting neck and axillae.

  • Confirmed by: presence of loose, wrinkled, and yellow skin. Involvement of arteries, e.g. presence of retinal angioid streaks.

  • Finalized by the predictable outcome of management, e.g. reducing cardiovascular risk factors.

Tuberous sclerosis

  • Suggested by: presence of skin lesions in a patient, usually a child with learning difficulties and epilepsy.

  • Confirmed by: multiple, red-yellow papules on face, especially on the nasal area and cheeks.

  • Finalized by the predictable outcome of management, e.g. genetic counselling, laser treatment for papules.

Nodules

Raised lesions >5mm diameter ± fixed to skin. Best viewed with magnifying glass. Patients usually report lesions because of unsightliness. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Sebaceous cyst

  • Suggested by: a smooth, spherical, dermal nodule, usually on back of head and neck.

  • Confirmed by: slowly growing over time. Sometimes a visible pole that periodically drains.

  • Finalized by the outcome of management, e.g. excision if distressing.

Lipoma

  • Suggested by: soft, ill-defined lesion.

  • Confirmed by: sometimes multiple in nature, soft consistency.

  • Finalized by the predictable outcome of management, e.g. excision if annoying.

Basal cell carcinoma

  • Suggested by: history of chronic solar damage, white-skinned, most commonly face and neck. Nodular, domed-shaped, necrozing in the centre, producing an ulcer with rolled edges.

  • Confirmed by: histology.

  • Finalized by the predictable outcome of management, e.g. cryotherapy, excision, or radiotherapy.

Warts

  • Suggested by: soft, ill-defined lesion.

  • Confirmed by: sometimes multiple in nature, soft consistency.

  • Finalized by the predictable outcome of management, e.g. excision if annoying.

Xanthoma

  • Suggested by: yellowish papules on the hands, tendons, and eyelids.

  • Confirmed by:fasting lipids.

  • Finalized by the predictable outcome of management, e.g. treating underlying hyperlipidaemia ± cauterization or excision.

Acne

  • Suggested by: young teen, oily skin.

  • Confirmed by: multiple comedones; open (blackhead spots) or closed (whitehead spots), in addition to papules and pustules, cysts, and scarring, depending on severity.

  • Finalized by the predictable outcome of management, e.g. washing face gently with cleanser but persistence for weeks, months or years. Topical and/or systemic treatment if severe.

Dermatofibroma

  • Suggested by: solitary or multiple nodules—exposed sites in limbs. History of minor injury, thorn pricks, or an insect bite, may be some FH.

  • Confirmed by: can hold the lesion between two fingers; feels like hard lump in dermis with the surface looking as if sucked in.

  • Finalized by the predictable outcome of management, e.g. excision biopsy.

Squamous cell carcinoma

  • Suggested by: background of solar damage. History of cumulative, previous skin lesion like Bowen’s disease. A crusted, thick, eroded nodule, usually on exposed sites.

  • Confirmed by: biopsy histology.

  • Finalized by the predictable outcome of management, e.g. excisional biopsy, radiotherapy.

Keratoacanthoma

  • Suggested by: history of prolonged sun exposure, suggested by rapidly growing tumour reaching a larger size, present on face, ears, or dorsa of hands.

  • Confirmed by: rapid growth for almost 2mo, followed by a static phase, and then involution—each stage lasting about 2mo. Biopsy result.

  • Finalized by the predictable outcome of management, e.g. curettage and histology.

Gouty tophi

  • Suggested by: history of recurrent joint pain. Cutaneous nodules with stretched over and normal texture skin, on the fingers usually, occasionally the ear.

  • Confirmed by: aspiration from tophi—uric acid crystals.

  • Finalized by the predictable outcome of management, e.g. analgesics, allopurinol ± excision of tophus.

Chondrodermatitis nodularis helicis externa

  • Suggested by: pressure effect on ear, especially when sleeping. Waking patient up from sleep due to pain.

  • Confirmed by: small, crusted nodule on the external ear.

  • Finalized by the predictable outcome of management, e.g. sleeping on the other side. Local injection of triamcinolone or excision.

Rheumatoid nodules

  • Suggested by: previously well-documented history of rheumatoid disease.

  • Confirmed by: presence of painless, small lumps under the skin and over pressure points (e.g. elbow), knuckles nodule typical on elbow. Multiple joint swelling and deformities. Rheumatoid factor +ve.

  • Finalized by the predictable outcome of management, e.g. analgesics, NSAIDs, avoiding irritating trauma, local steroid injections, or excision of nodules.

Heberden’s nodes

  • Suggested by: history of chronic osteoarthritis.

  • Confirmed by: presence of painless, small nodes (bony growths) on the terminal interphalangeal joints.

Pyogenic granuloma

  • Suggested by: rapidly growing, vascular nodule, easily bleeds.

  • Confirmed by: excision biopsy, histology.

  • Finalized by the predictable outcome of management, e.g. ‘shave biopsy’, curettage, and electrocautery.

Malignant melanoma

  • Suggested by: FH, fair skin, multiple moles, by mole being asymmetrical in shape, irregular border, deep black or two colours, and >7mm in diameter.

  • Confirmed by: excision + histology of lesion

  • Finalized by the predictable outcome of management, e.g. excisional biopsy, etc.

Erythema nodosum

  • Suggested by: red, tender, deeply placed nodules, usually on the shin. Multiple and bilateral. Associated fever and joint pain. Can be idiopathic or associated with infection or inflammatory bowel disease.

  • Confirmed by:ESR; CXR: bilateral, hilar lymphadenopathy.

  • Finalized by the predictable outcome of management, e.g. analgesics, NSAIDs with or without systemic steroids.

Polyarteritis nodosa

  • Suggested by: tender nodules, fever, joint pain, neuropathic symptoms.

  • Confirmed by:ESR, +ve autoimmune profile, +ve p-ANCA.

  • Finalized by the predictable outcome of management, e.g. analgesics, NSAIDs.

Lepromatous leprosy

  • Suggested by: multiple pale nodules on face, ears, and other places.

  • Confirmed by: microbiology, biopsy.

  • Finalized by the predictable outcome of management, e.g. combination of rifampicin, clofazimine, and dapsone for 2y.

2° syphilis

  • Suggested by: history of ulcers in genitalia. Nodular scaly lesion on hands and soles. Constitutional symptoms.

  • Confirmed by: serological tests, microbiology.

  • Finalized by the predictable outcome of management, e.g. benzylpenicillin IM.

Lupus vulgaris

  • Suggested by: slow onset over months to years, hyperkeratotic, crusted nodule, usually at the site of accidental inoculation.

  • Confirmed by: +ve tuberculin test. +ve microbiology for mycobacterium.

  • Finalized by the predictable outcome of management, e.g. antituberculosis combination treatment. Surgical excision for early lesions.

Fish tank or swimming pool granuloma

  • Suggested by: occupation or hobbies bring the patient in contact with fish, or history of trauma treated in the past with antibiotics with no response.

  • Confirmed by: +ve microbiology tests for mycobacterium.

  • Finalized by the predictable outcome of management, e.g. antibiotics as per culture and sensitivity.

Blisters

Blisters <0.5cm diameter are vesicles, blisters >0.5cm are bullae. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Skin friction

  • Suggested by: presence of blister friction marks on skin and a possible bruising.

  • Confirmed by: history of traumatic friction.

  • Finalized by the predictable outcome of management, e.g. keep clean, intact. If bursts, get rid of remaining fluid, then apply clean dressing.

Thermal burns

  • Suggested by: presence of blister possibly with some erythema.

  • Confirmed by: history of burn.

  • Finalized by the predictable outcome of management, e.g. to relieve pain with waterproof antiseptic dressing (to prevent transpiration from damaged cells). Assess the degree of burn and treat accordingly.

Leg oedema

  • Suggested by: blister in the presence of swollen legs.

  • Confirmed by: presence of severe pitting oedema, resolution when oedema treated.

  • Finalized by the predictable outcome of management, e.g. diuretics, treat associated infections and the underlying cause of oedema if any.

Chemical burns

  • Suggested by: presence of blisters, possibly with traces of chemical.

  • Confirmed by: history of contact with chemical.

  • Finalized by the predictable outcome of management, e.g. pain control, assessment of degree of the burn, and treat accordingly.

Insect bites

  • Suggested by: history of contact with insect.

  • Confirmed by: site of sting surrounded by redness.

  • Finalized by the predictable outcome of management, e.g. paracetamol and antihistamines.

Chicken pox

  • Suggested by: contact with a case of chickenpox, a prodromal illness for 1–2d before the appearance of a rash.

  • Confirmed by: erythematous lesions, rapidly changing to vesicles, then pustules, followed by crusts after 2–3d. Lesions itchy.

  • Finalized by the predictable outcome of management, e.g. antipyretics, antihistamines, and calamine lotion to ease itching and irritability.

Herpes simplex

  • Suggested by: presence of contacts and occurring at a similar site each time, usually lips, face, or genitals, associated respiratory infection (‘cold sore’). Lesions recurring.

  • Confirmed by: presence of vesicles on the mouth or genitalia. Painful, later crusting with local lymphadenopathy.

  • Finalized by the predictable outcome of management, e.g. paracetamol for pain. Aciclovir cream applied five times daily for recurrent mild facial and genital infections. Aciclovir orally for more severe infections. Confirmed genital herpes in a pregnant woman at the time of delivery is an indication for Caesarean section.

Herpes zoster

  • Suggested by: pain, tenderness and paraesthesia in the affected area before the appearance of the rash.

  • Confirmed by: presence of typical lesions, which are usually unilateral.

  • Finalized by the predictable outcome of management, e.g. for mild causes—analgesics, rest; local calamine lotion for more severe cases; and if seen within 72h of the rash appearance, give aciclovir 800mg five times daily for 1wk.

Herpetic whitlow

  • Suggested by: a painful lesion on finger, usually in a nurse or a dentist attending a patient with herpetic lesion, or in sportsmen like wrestlers (direct inoculation).

  • Confirmed by: presence of a painful vesicular lesion on a finger.

  • Finalized by the predictable outcome of management, e.g. paracetamol for pain. Aciclovir cream or tablets, depending on severity.

Hand, foot, and mouth disease

  • Suggested by: presence of prodromal symptoms before the appearance of lesions restricted to the feet, hands, and mouth in a child or an adult.

  • Confirmed by: presence of vesicles surrounded by an intense skin erythema on the palms, soles, and in the mouth.

  • Finalized by the predictable outcome of management, e.g. analgesia, and the self-limiting nature of the condition.

Pompholyx

  • Suggested by: history of atopy, stress, allergic reactions to fungal infections elsewhere.

  • Confirmed by: presence of persistent, itchy, clear blisters on fingers, sometimes palms.

  • Finalized by the predictable outcome of management, e.g. symptomatic treatments.

Acute eczema: contact dermatitis or atopic

  • Suggested by: acute onset affecting a particular site, suggesting contact with certain objects. History of occupation, hobbies, or nickel sensitivity can suggest a clue.

  • Confirmed by: presence of vesicles, and sometimes large blisters with erythema, oedema, papules, and vesicles seen on the affected part.

  • Finalized by the predictable outcome of management, e.g. avoid contact with allergens, if possible; moisturizers, creams, and topical steroids. Topical or systemic antibiotic if there is infection.

Pemphigus

  • Suggested by: presence of superficial blisters on the scalp, face, back, chest, and flexures. These may be preceded by mouth erosions several weeks or months before. History of other autoimmune disease like hypothyroidism or myasthenia gravis.

  • Confirmed by: presence of IgG auto-antibodies to epidermal components. Direct immunofluorescence studies show deposition of IgG antibodies in epidermis.

  • Finalized by the predictable outcome of management, e.g. high dose of prednisolone PO (e.g. 1–1.5mg/kg/d) ± azathioprine or cyclophosphamide.

Pemphigoid

  • Suggested by: tense, large blisters, arising on a red or a normal-looking skin, usually in an elderly patient, on the limbs, trunk and flexures, and very rarely, in the mouth.

  • Confirmed by: specific IgG antibodies to the antigens BP230 and BP180 in subepidermal area. Direct immunofluorescence studies showing IgG and C3 antibodies in subepidermal area.

  • Finalized by the predictable outcome of management, e.g. usually a low dose of prednisolone PO, e.g. 30–60mg daily with or without azathioprine.

Dermatitis herpetiformis associated with gluten enteropathy

  • Suggested by: a young adult male with gluten sensitivity, with small symmetrical, very itchy blisters on the extension surfaces.

  • Confirmed by: direct immunofluorescence studies showing depositions and IgA antibodies in the dermis.

  • Finalized by the predictable outcome of management, e.g. use of local and systemic antibiotics.

Bullous impetigo

  • Suggested by: presence of extensive, non-itchy golden or brown blisters, on face and limbs in children and adults.

  • Confirmed by: isolation of Staphylococcus in the blister fluid.

  • Finalized by the predictable outcome of management, e.g. use of local and systemic antibiotics.

Bullous drug eruption

  • Suggested by: use of a drug in the preceding 2–3 wk, e.g. barbiturates, furosemide.

  • Confirmed by: accurate prescribing records of potential causal drug. +ve patch or intradermal tests.

  • Finalized by the predictable outcome of management, e.g. withdrawal of the causative drug. Emollients and/or topical steroids.

  • Erythema multiforme

  • a severe form involving mucous membranes called Stevens–Johnson syndrome

  • Suggested by: presence of a potential cause like drug or infection.

  • Confirmed by: presence of red rings with a central pale or purple area, giving the appearance of an ‘iris’ or a target lesion which then blisters.

  • Finalized by the predictable outcome of management, e.g. identification and treatment of the underlying cause. Symptomatic treatment for mild cases and hospital admission, for sever ones.

Pemphigoid gestationis

  • Suggested by: presence of similar bullae lesions during previous pregnancies, subsided after delivery.

  • Confirmed by: presence of intensely itchy bullae associated with pregnancy.

  • Finalized by the predictable outcome of management, e.g. prednisolone PO, e.g. 30–60mg daily.

Porphyrias

  • Suggested by: presence of other affected members in the family. Lesions consist of painful red blistering eruptions.

  • Confirmed by: presence of porphyrins in blood and urine, gene studies.

  • Finalized by the predictable outcome of management, e.g. avoid sun exposure, alcohol, or aggravating drugs. Correct iron deficiency if present.

Toxic epidermal necrolysis

  • Suggested by: severe bullous eruption when taking an anticonvulsant, antibiotic, or allopurinol.

  • Confirmed by: associated severe epidermal loss.

  • Finalized by the predictable outcome of management, e.g. hospital admission, usually on an ITU ward.

Epidermolysis bullosa

  • Suggested by: blistering of skin after minimal trauma.

  • Confirmed by: genetic studies (mapped to chromosomes 12 and 17). Prenatal diagnosis.

  • Finalized by the predictable outcome of management, e.g. avoidance of trauma, supportive measures, and treatment of infection.

Erythema

Reddening of the skin that blanches on pressure. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Cellulitis

  • Suggested by: painful red area on a limb, fever. An underlying condition, e.g. diabetes mellitus.

  • Confirmed by: swelling, redness, localized pain, malaise.

  • Finalized by the predictable outcome of management, e.g. antibiotic effective against Streptococcus or Staphylococcus, e.g. benzylpenicillin, etc. and flucloxacillin may be IV initially.

Gout

  • Suggested by: severe joint redness, pain, and swelling, usually in one joint, commonly that of the big toe.

  • Confirmed by: iserum uric acid and the presence of urate crystals in joint fluid aspirate.

  • Finalized by the predictable outcome of management, e.g. indometacin or, if contraindicated, colchicine to a maximum of 6mg until pain disappears or side-effects appear. Long term allopurinol.

Thermal burn

  • Suggested by: presence of blister, possibly with some erythema.

  • Confirmed by: history of burn.

  • Finalized by the predictable outcome of management, e.g. relieve pain with sterile, waterproof dressing to prevent transpiration from damaged cells. Assess the degree of burn and treat accordingly.

Chemical burn

  • Suggested by: the presence of blisters, possibly with traces of chemical.

  • Confirmed by: history of chemical burn.

  • Finalized by the predictable outcome of management, e.g. pain control with sterile, waterproof dressing to prevent transpiration from damaged cells, assessment of degree of the burn, and treat accordingly.

Sunburn

  • Suggested by: history of exposure to sun.

  • Confirmed by: redness of exposed area.

  • Finalized by the predictable outcome of management, e.g. no more sun. Soothing ointments; antihistamine if heat and cold intolerance due to loss of temperature regulation.

Drug eruption

  • Suggested by: intake of a drug in the preceding 2–3wk.

  • Confirmed by: accurate prescribing records. Patch skin testing.

  • Finalized by the predictable outcome of management, e.g. withdrawal of causative drug. Emollients and/or topical steroids.

Fixed drug eruptions

  • Suggested by: appearance of the rash at the same place every time the same drug taken.

  • Confirmed by: patch skin testing.

  • Finalized by the predictable outcome of management, e.g. avoiding the causative drug.

Viral toxic erythema

  • Suggested by: systemic symptoms with no obvious focus of infection in a child.

  • Confirmed by: resolution when systemic symptoms resolve.

  • Finalized by the predictable outcome of management, e.g. symptomatic treatment.

Rosacea

  • Suggested by: facial erythema in middle-aged males or females.

  • Confirmed by: presence of flushes, erythema, telangiectasis, papules, and pustules. Sometimes the presence of rhinophyma (a red, lobulated nose). No comedones as in acne.

  • Finalized by the predictable outcome of management, e.g. topical metronidazole 0.75% cream twice daily or tetracycline PO for 3–4wk, reduced dose for 2–3mo.

Palmar erythema

  • Suggested by: associated evidence of liver cirrhosis, pregnancy, and polycythaemia.

  • Confirmed by: resolution with underlying condition.

  • Finalized by the predictable outcome of management, e.g. treatment of underlying cause.

Drug phototoxicty

  • Suggested by: taking a drug and rash in areas exposed to sunlight.

  • Confirmed by: disappearance of the rash after discontinuing the offending drug.

  • Finalized by the predictable outcome of management, e.g. discontinuation of the offending drug. Emollients and/or topical steroids.

Erythema multiforme due to sarcoidosis

  • Suggested by: red, tender, deeply placed nodules, usually on the shin. Multiple and bilateral. Associated facet and joint pain.

  • Confirmed by:ESR; CXR: bilateral, hilar lymphadenopathy.

  • Finalized by the predictable outcome of management, e.g. analgesics, NSAIDs ± systemic steroids.

Systemic lupus erythematosus (SLE)

  • Suggested by: facial butterfly eruptions commonly in females, with evidence of multisystem involvement.

  • Confirmed by: antinuclear auto-antibodies.

  • Finalized by the predictable outcome of management, e.g. sunscreens if multisystemic disease, steroids with or without immunosuppressive agents.

Erythema ab igne

  • Suggested by: history of an erythema on the shin of an elderly patient who sits before an open fire.

  • Confirmed by: improving when avoiding sitting in front of a fire.

  • Finalized by the predictable outcome of management, e.g. stop causative behaviour.

Livedo reticularis

  • Suggested by: cyanotic, net-like discoloration skin of legs.

  • Confirmed by: presence of an underlying cause, e.g. exposure to cold, SLE, and polycythaemia.

  • Finalized by the predictable outcome of management, e.g. treat underlying cause.

HIV seroconversion

  • Suggested by: fever, malaise, nausea, and vomiting with lymphadenopathy, erythematous rash in a homosexual or IV drug-user.

  • Confirmed by: detection of P24 antigen or HIV RNA by PCR.

  • Finalized by the predictable outcome of management, e.g. of underlying disease.

Erythema nodosum (sarcoid, tuberculosis (TB), drugs, Streptococcus)

  • Suggested by: presence of tender, reddish-blue nodules, usually on the calves and shins, and presence of an underlying condition, e.g. bacterial, viral, fungal, drugs, and systemic disease.

  • Confirmed by: skin biopsy.

  • Finalized by the predictable outcome of management, e.g. pain relief by analgesics or NSAIDs.

Erythema induratum (TB: Bazin’s disease)

  • Suggested by: presence of red, indurated lesions on the lower legs.

  • Confirmed by: biopsy of lesion.

  • Finalized by the predictable outcome of management, e.g. analgesia. Treat underlying cause.

Erythema chronicum migrans (Lyme disease)

  • Suggested by: slowly expanding erythematous ring at the site of a tic bite, on a limb usually ± multisystem symptoms.

  • Confirmed by: serology.

  • Finalized by the predictable outcome of management, e.g. doxycyline for 2–3wk. In children below 8y and in pregnancy: amoxicillin for a similar period.

Purpura and petechiae

Purplish lesions resulting from free red blood cells in the skin. They do not blanch on pressure. Purpurae are large (>5mm) and imply clotting defects or blood vessel fragility; petechiae are small (<5mm) and imply platelet defects or vasculitis. Initial investigations (other tests in bold below): digital photography of lesion, FBC, U&E, LFT.

Main differential diagnoses and typical outline evidence, etc.

Trauma

  • Suggested by: history.

  • Confirmed by: lesions matching site of trauma.

  • Finalized by the predictable outcome of management, e.g. symptomatic treatment.

Senile purpura

  • Suggested by: elderly patient.

  • Confirmed by: atrophic small veins and skin.

  • No treatment, just reassurance.

Liver disease

  • Suggested by: jaundice, hepatomegaly, etc.

  • Confirmed by: abnormal LFT and ultrasound (US) scan of liver.

  • Finalized by the predictable outcome of management, e.g. treat underlying condition.

Raised venous pressure, e.g. vomiting

  • Suggested by: history of vomiting, etc.

  • Confirmed by: presence of purpuric spot, usually around the eyes.

  • Finalized by the predictable outcome of management, e.g. spontaneous resolution.

Drugs (steroids, warfarin, aspirin)

  • Suggested by: intake of drugs.

  • Confirmed by: disappearance when drug stopped.

  • Finalized by the predictable outcome of management, e.g. resolution after discontinuation of the causative agent.

Vasculitis (Henoch–Schönlein, connective tissue)

  • Suggested by: purpurae on buttock and extensor surfaces, typically in a young male. Associated features of cause, e.g. proteinuria, hypertension, and abdominal pain of Henoch–Schönlein syndrome.

  • Confirmed by: typical appearance of the rash.

  • Finalized by the predictable outcome of management, e.g. treatment of underlying cause, e.g. with systemic steroids.

Thrombocytopaenia (e.g. idiopathic thrombocytopaenic purpura (ITP), drug-induced, bone marrow replacement, aplastic anaemia)

  • Suggested by: features of the underlying cause.

  • Confirmed by: FBC: dplatelets, etc.

  • Finalized by the predictable outcome of management, e.g. resolution after treating the underlying condition.

Renal failure

  • Suggested by: symptoms and signs of renal impairment.

  • Confirmed by:urea, ↑creatinine.

  • Finalized by the predictable outcome of management, e.g. of underlying condition.

Endocarditis

  • Suggested by: presence of fever, general malaise, heart murmur.

  • Confirmed by: +ve blood cultures and an abnormal echocardiogram.

  • Finalized by the predictable outcome of management, e.g. benzylpenicillin IV + gentamicin.

Paraproteinaemia

  • Suggested by: back pain, loss of appetite, high temperature.

  • Confirmed by: paraprotein on electrophoresis.

  • Finalized by the predictable outcome of management, e.g. treatment of underlying cause.

Clotting disorder (haemophilia A and B)

  • Suggested by: easy bleeding into muscles and joints, and delayed clotting.

  • Confirmed by: clotting screen.

  • Finalized by the predictable outcome of management, e.g. vitamin K; treatment of clotting defect.

Meningoccocal septicaemia

  • Suggested by: rapidly progressive disease with headaches, neck stiffness, vomiting, and photophobia.

  • Confirmed by: blood culture and lumbar puncture.

  • Finalized by the predictable outcome of management, e.g. benzylpenicillin IM.

Vitamin K deficiency

  • Suggested by: disorder in a patient with malnutrition or malabsorption, gastrointestinal (GI) bleeding.

  • Confirmed by: reversal of bleeding when supplied with vitamin K.

  • Finalized by the predictable outcome of management, e.g. vitamin K replacement.

Vitamin C deficiency

  • Suggested by: anorexia, cachexia, gingivitis, loose teeth, and halitosis; pregnancy, poverty, odd diet.

  • Confirmed by: low vitamin C level.

  • Finalized by the predictable outcome of management, e.g. vitamin C supplement.

Disseminated intravascular coagulation (DIC)

  • Suggested by: severe bruising and failure to clot after starting to bleed. Features of a severe underlying condition such as malignancy, sepsis, trauma, and obstetric emergencies.

  • Confirmed by: FBC: ↓platelets, ↑PT, ↑APTT, ↓fibrinogen.

  • Finalized by the predictable outcome of management, e.g. treatment of the cause, and replacement of platelets and clotting factors.

Pustules

A well-defined, pus-filled lesion. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Impetigo

  • Suggested by: presence of easily ruptured vesicles, leaving yellow crusted exudates, usually affect the face and extremities.

  • Confirmed by: typical look and site of lesion.

  • Finalized by the predictable outcome of management, e.g. local or systemic antibiotics, depending on severity.

Folliculitis

  • Suggested by: lesions being in hair-baring areas—in women, there might be a history of hair removal by shaving or waxing.

  • Confirmed by: swab: isolation S. aureus.

  • Finalized by the predictable outcome of management, e.g. local or systemic antibiotics.

Sycosis barbae

  • Suggested by: folliculitis in the beard area.

  • Confirmed by: swab isolation of S. aureus.

  • Finalized by the predictable outcome of management, e.g. local or systemic antibiotics.

Herpes simplex

  • Suggested by: presence of contacts and occurring at a similar site each time, usually lips, face, or genitals, and sometimes the presence of a respiratory infection, therefore called a ‘cold sore’. Lesions recurring.

  • Confirmed by: presence of painful vesicles on the mouth or genitalia.

  • Finalized by the predictable outcome of management, e.g. paracetamol for pain. Aciclovir cream applied five times daily for recurrent mild facial and genital infections, and aciclovir PO for more severe infections. Confirmed genital herpes in a pregnant woman at the time of delivery is an indication for Caesarean section.

Herpes zoster

  • Suggested by: pain, tenderness, and paraesthesia in the affected area before the appearance of the rash.

  • Confirmed by: presence of typical lesions which are normally unilateral.

  • Finalized by the predictable outcome of management, e.g. for mild causes—analgesics, rest, local calamine lotion; for more severe cases and if seen within 72h of the rash appearance, give aciclovir 800mg five times daily for 1wk.

Acne vulgaris

  • Suggested by: presence of comedones, open (blackheads) or closed (whiteheads), papules, pustules, cysts, or scars depending on severity. Comedones appear first at around the age of 12y, then evolve into the different other lesion.

  • Confirmed by: typical features of the skin lesions.

  • Finalized by the predictable outcome of management, e.g. for mild acne, use local treatments (e.g. benzoyl peroxide cream or gel bd, tretinoin cream or gel) or local antibiotic gels like Zineryt®, with or without oral antibiotic, e.g. minocycline.

Rosacea

  • Suggested by: facial erythema in middle-aged males or females.

  • Confirmed by: flushes, erythema, telangiectasis, papules and pustules ± rhinophyma (a red lobulated nose). No comedones as in acne.

  • Finalized by the predictable outcome of management, e.g. topical metronidazole or tetracycline PO for 3–4wk with lower dose for 2–3mo.

Hydranitis suppurativa

  • Suggested by: pustules in axilla, groin.

  • Confirmed by: recurrent problem.

  • Finalized by the predictable outcome of management, e.g. local or systemic antibiotics.

Candidiasis

  • Suggested by: itchy, symmetrical with ‘satellite’ pustules outside the outer edge of the skin rash. Underlying conditions, e.g. diabetes mellitus, AIDS or Cushing’s.

  • Confirmed by: swabs and skin scrapings.

  • Finalized by the predictable outcome of management, e.g. local clotrimazole or miconazole for 2–4wk. Systemic treatment such as fluconazole for non-responding cases.

Localized pustular psoriasis

  • Suggested by: chronic nature of the illness in an elderly patient with psoriasis elsewhere.

  • Confirmed by: presence of pustules surrounded by a scaly, erythematous skin on the palms and soles.

  • Finalized by the predictable outcome of management, e.g. moderate to potent strength topical steroid.

Generalized pustular psoriasis

  • Suggested by: acute onset with fever, malaise, and general ill health with a psoriatic rash.

  • Confirmed by: presence of sheets of small, yellowish pustules, on an erythematous background, which may spread rapidly.

  • Finalized by the predictable outcome of management, e.g. rehydration IV with or without antibiotics + local measures.

Dermatitis herpetiformis associated with gluten enteropathy

  • Suggested by: a young adult male with gluten sensitivity, with small, symmetrical, very itchy blisters in the extensor surfaces.

  • Confirmed by: direct immunofluorescence studies showing depositions and IgA antibodies in the dermis.

  • Finalized by the predictable outcome of management, e.g. local and systemic antibiotics.

Pseudomonas infection

  • Suggested by: history of long-term treatment of acne (if lesions are on face) or history of exposure to contaminated baths or whirlpools (if lesions are on body).

  • Confirmed by: swabs + isolation of organism, culture and sensitivity.

  • Finalized by the predictable outcome of management, e.g. with appropriate antibiotic based on culture and sensitivity.

Drug reactions

  • Suggested by: intake of a potentially causative drug in the preceding 2–3wk.

  • Confirmed by: accurate prescribing records. Patch test.

  • Finalized by the predictable outcome of management, e.g. withdrawal of the causative drug. Emollients and/or topical steroids.

Hyperkeratosis, scales, and plaques

Hyperkeratosis: thickening of the keratin layer; scale: fragment of dry skin; plaque: raised flat-topped lesion, usually over 2cm in diameter. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Psoriasis

  • Suggested by: scaly, silvery scales on extensor surfaces and sites of minor trauma (Koebner’s phenomenon); lesions usually clear after exposure to sun.

  • Confirmed by: typical presence of plaques of scaly lesions covering extensor areas of trunk and limbs.

  • Finalized by the predictable outcome of management, e.g. tar preparation, Dovobet®, short contact dithranol, or UVB. Immunosuppressants for extensive lesions.

Chronic eczema: atopic, contact

  • Suggested by: contact with certain objects or history of atopy.

  • Confirmed by: improvement of condition after eliminating the offending subject.

  • Finalized by the predictable outcome of management, e.g. removal of the cause; moisturizers, creams, and topical steroids. Antibiotics if there is infection.

Fungal infections

  • Suggested by: typical ring-like lesions (clearer centres) on the trunk and limbs in tinea corporis (ringworm) or lesions in the inner upper thigh, not involving the scrotum with an advancing scaly and pustular edge in tinea cruris.

  • Confirmed by: microscopy and culture of skin scrapings. Wood’s UV light examination for tinea capitis.

  • Finalized by the predictable outcome of management, e.g. local or systemic antifungal agents.

Seborrhoeic dermatitis

  • Suggested by: scalp and facial involvement, excessive dandruff with an itchy and scaly eruption, affecting sides of nose, scalp margin, eyebrows, and ear.

  • Confirmed by: typical skin lesions and distribution.

  • Finalized by the predictable outcome of management, e.g. medicated shampoo alone or following the application of 2% sulphur ± preceding 2% salicylic acid for scalp lesions. Facial lesions treated with combined antimicrobial and steroid creams.

Lichen simplex chronicus

  • Suggested by: history of repeated rubbing or scratching of an area as a habit or caused by stress; typically Asian or Chinese patient.

  • Confirmed by: presence of a single plaque on the back of the neck or in the perineum.

  • Finalized by the predictable outcome of management, e.g. emollients and topical steroids.

Lichen planus

  • Suggested by: no FH, related to stress; presence of Koebner’s phenomenon.

  • Confirmed by: itchy, well-defined, raised, shiny-surfaced lesions with a violaceous colour divided by white streaks (Wickman’s striae).

  • Finalized by the predictable outcome of management, e.g. topical steroids, systemic steroids for very extensive lesions.

Solar keratosis

  • Suggested by: lesions on sites exposed to sun, patients work out of doors or history of excessive sunbathing, pipe smokers.

  • Confirmed by: raised keratotic lesion <1cm in diameter with an irregular edge on face, back of the hands, arms and legs, and scalp in bald men. Lesions are pre-malignant.

  • Finalized by the predictable outcome of management, e.g. cryotherapy for large and multiple lesions; trial of fluorouracil cream bd for 2wk.

Pityriasis versicolor

  • Suggested by: chronic brown or pinkish oval or round scaly patches on trunk and limbs; hypopigmented spots in tanned or racially dark skin.

  • Confirmed by: typical appearance on microscopy of skin scrapings.

  • Finalized by the predictable outcome of management, e.g. clotrimazole or miconazole creams, or the use of topical selenium sulphide or ketoconazole shampoos applied for 30min, and then washed off tds for 2wk. If resistant, itraconazole PO for 1wk.

Pityriasis rosea

  • Suggested by: acute onset of scaly oval papules, mainly on trunk, preceded by a 2–8cm in diameter single lesion called the ‘herald patch’.

  • Confirmed by: typical appearance of the rash and the herald patch.

  • Finalized by the predictable outcome of management, e.g. symptomatic treatment.

Juvenile plantar dermatosis

  • Suggested by: child <10y, wearing socks and shoes made of synthetic material.

  • Confirmed by: presence of red, dry, fissured, and shiny skin, usually on the forefoot ± the whole sole.

  • Finalized by the predictable outcome of management, e.g. use of emollients.

Guttate psoriasis

  • Suggested by: acute, symmetrical appearance of drop-like, scaly skin lesions, on trunk and limbs in an adolescent or young adult typically with sore throat.

  • Confirmed by: typical appearance of the rash.

  • Finalized by the predictable outcome of management, e.g. topical steroids, coal tar, or narrow band UV.

Bowen’s disease

  • Suggested by: indurated, crusted, well-defined, erythematous macule trunk or limbs ± exposure to sheep dip or weed-killers.

  • Confirmed by: biopsy: carcinoma in situ.

  • Finalized by the predictable outcome of management, e.g. cryotherapy, topical fluorouracil cream, photodynamic therapy.

Mycosis fungoides (cutaneous T-cell lymphoma)

  • Suggested by: scaly, erythematous patches progressing over months to years to fixed infiltrated plaques, then cancerous nodules.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. topical steroids PUVA, or electron beam therapy depending on severity.

  • Drug-induced

  • (e.g. β-blockers, carbamazepine)

  • Suggested by: history of taking suspected drug in the preceding 2–3wk.

  • Confirmed by: accurate prescribing records. Patch test.

  • Finalized by the predictable outcome of management, e.g. withdrawal of causative drug. Emollients and/or topical steroids.

Ichthyosis

  • Suggested by: mild to severe dry, scaly skin, seen mainly on the extensor surfaces with the flexures often spared ± FH.

  • Confirmed by: typical appearance of skin and biopsy.

  • Finalized by the predictable outcome of management, e.g. emollients and bath oils for mild cases.

Keratoderma

  • Suggested by: gradual onset in middle age, typically in post-menopausal female.

  • Confirmed by: hyperkeratosis of palms and soles.

  • Finalized by the predictable outcome of management, e.g. 5–10% salicylic acid ointment or 10% urea cream.

Erythroderma due to eczema, psoriasis, and lymphoma

  • Suggested by: severe systemic symptoms with patchy, then generalized erythema followed by scaling days later ± features of an underlying cause.

  • Confirmed by: skin biopsy.

  • Finalized by the predictable outcome of management, e.g. hospital admission for IV. fluids and steroids.

2° syphilis

  • Suggested by: history of previous chancre + presence of a non-itchy, pink-coloured, papular eruption, becoming scaly, on the trunk, limbs, palms, and soles.

  • Confirmed by: +ve serology for syphilis.

  • Finalized by the predictable outcome of management, e.g. benzyl-penicillin IM or Penicillin V orally for 14d (or doxycycline, erythromycin).

Itchy scalp

Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Head lice

  • Suggested by: intense itching of scalp, typically in a school child ± poor social and hygienic conditions.

  • Confirmed by: seeing nits or lice on hair shafts.

  • Finalized by the predictable outcome of management, e.g. malathion applied to scalp and left for 12h before being washed out, to be repeated in a week’s time. Nits can be removed with a comb.

Seborrhoeic eczema

  • Suggested by: scalp and facial involvement, excessive dandruff with an itchy and scaly eruption, affecting sides of nose, scalp margin, eyebrows, and ear.

  • Confirmed by: the above typical skin lesions and distribution.

  • Finalized by the predictable outcome of management, e.g. medicated shampoo alone or 2% sulphur or 2% salicylic acid for scalp lesions. Facial lesions: combined antimicrobial and steroid creams.

Psoriasis

  • Suggested by: onset after period of stress, lesions at sites of minor trauma (Koebner’s phenomenon) clearing after exposure to sun.

  • Confirmed by: well-defined, raised, scaly, disc-shaped plaques on scalp hair margin.

  • Finalized by the predictable outcome of management, e.g. 3% salicylic acid in a cream base applied daily in combination with a tar-containing shampoo. Trial of coconut oil compound.

Lichen simplex chronicus

  • Suggested by: history of repeated rubbing or scratching of an area habitually or during stress; typically Asian or Chinese.

  • Confirmed by: single plaque on the back of the neck or in the perineum.

  • Finalized by the predictable outcome of management, e.g. emollients and topical steroids.

Allergic contact dermatitis

  • Suggested by: exposure to suspect precipitant, e.g. hair dye.

  • Confirmed by: improvement on removal of the offending agent.

  • Finalized by the predictable outcome of management, e.g. avoid causative agent. Local steroid lotions.

Fungal infection (complicated by possible irreversible hair loss, if untreated)

  • Suggested by: mild, scaly, inflammatory areas with alopecia and broken hair shafts or an inflamed boggy pustular swelling called kerion.

  • Confirmed by: microscopy and culture of skin scrapings.

  • Finalized by the predictable outcome of management, e.g. griseofulvin for 1–2mo.

Herpes zoster

  • Suggested by: pain, tenderness, and paraesthesia in the affected area before the appearance of rash.

  • Confirmed by: presence of typical unilateral lesions.

  • Finalized by the predictable outcome of management, e.g. mild—analgesics, rest; local calamine lotion; if severe and seen within 72h of rash appearing: aciclovir, e.g. 800mg five times daily for 1wk.

Anxiety and depression

  • Suggested by: history of low mood, anxiety.

  • Confirmed by: normal appearance of scalp initially and on follow-up.

  • Finalized by the predictable outcome of management, e.g. explanation, psychotherapy.

Itchy skin with lesions but no wheals

Skin scratched or rubbed ± a number of secondary skin signs: excoriations (scratch marks), lichenification (skin thickening), papules (localized skin thickening), or nodules. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Allergic contact dermatitis

  • Suggested by: exposure to a potential allergen, e.g. hair dye.

  • Confirmed by: improvement on removal of the offending agent.

  • Finalized by the predictable outcome of management, e.g. avoid causative agent. Local steroid lotions.

Candidiasis e.g. due to diabetes mellitus, AIDS, or Cushing’s syndrome

  • Suggested by: itchy, symmetrical with ‘satellite’ pustules outside the outer edge of the skin rash. Symptoms and signs of underlying condition.

  • Confirmed by: +ve swabs and skin scrapings for yeasts.

  • Finalized by the predictable outcome of management, e.g. local clotrimazole or miconazole for 2–4wk. Systemic treatment for non-responding cases.

Discoid eczema

  • Suggested by: recurring itchy lesion in a middle-aged or an elderly man.

  • Confirmed by: presence of coin-shaped lesions on the limbs with a symmetrical distribution.

  • Finalized by the predictable outcome of management, e.g. potent steroid cream combined with an antibiotic.

Drug-induced eczema

  • Suggested by: itchy skin with a history of recent drug ingestion.

  • Confirmed by: improvement on withdrawal of offending agent.

  • Finalized by the predictable outcome of management, e.g. removal of the offending agent. Topical emollients and steroids.

Varicose eczema

  • Suggested by: associated varicose veins and swollen oedematous leg.

  • Confirmed by: presence of an eczematous patch on the medial aspect of leg.

  • Finalized by the predictable outcome of management, e.g. diuretics, leg elevation, compression bandage, emollient, and steroid creams.

Scabies

  • Suggested by: severe itching, especially at night; other member of family affected.

  • Confirmed by: presence of burrows on sides of fingers, wrists, ankles, and nipples. Microscopic examination showing the mites.

  • Finalized by the predictable outcome of management, e.g. malathion lotion applied on whole body for 24h ± reapplication after 2wk. Treat all close contacts. Wash all clothes and bedding.

Seborrhoeic dermatitis

  • Suggested by: scalp and facial involvement, excessive dandruff with an itchy and scaly eruption affecting sides of nose, scalp margin, eyebrows, and ear.

  • Confirmed by: typical skin lesions and distribution.

  • Finalized by the predictable outcome of management, e.g. medicated shampoo alone ± preceding 2% sulphur or 2% salicylic acid. Facial lesions treated with combined antimicrobial and steroid creams.

Asteatotic eczema

  • Suggested by: history of dryness and itching in elderly patient, excessive use of central heating, and washing.

  • Confirmed by: presence of a scaly, red rash; in severe forms, fissuring and inflammation on leg.

  • Finalized by the predictable outcome of management, e.g. emollients with or without topical steroids.

Dermatitis herpetiformis associated with gluten enteropathy

  • Suggested by: a young adult male with gluten sensitivity, with small symmetrical, very itchy blisters in the extensor surfaces.

  • Confirmed by: direct immunofluorescence studies showing depositions and IgA antibodies in the dermis.

  • Finalized by the predictable outcome of management, e.g. local and systemic antibiotics.

Lichen planus

  • Suggested by: related to stress and the presence of Koebner’s phenomenon.

  • Confirmed by: presence of itchy, well-defined, and raised, shiny-surfaced lesions with a violaceous colour interpreted by white streaks (Wickman’s striae).

  • Finalized by the predictable outcome of management, e.g. topical steroids; systemic steroids for very extensive lesions.

Psoriasis

  • Suggested by: scaly, silvery scales on extensor surfaces and sites of minor trauma (Koebner’s phenomenon); lesions usually clear after exposure to sun.

  • Confirmed by: typical presence of plaques of scaly lesions covering extensor areas of trunk and limbs.

  • Finalized by the predictable outcome of management, e.g. tar preparation, Dovobet®, short contact dithranol or UVB. Immunosuppressants for extensive lesions.

Eczema herpeticum

  • Suggested by: previous history of atopic eczema in a child who is generally unwell.

  • Confirmed by: presence of herpetic lesions on a background of eczematous skin.

  • Finalized by the predictable outcome of management, e.g. admission to hospital for fluids IV + aciclovir.

Lichen sclerosus

  • Suggested by: presence of lesion on the genitals and perineum in a female. History of autoimmune conditions, e.g. vitiligo and pernicious anaemia.

  • Confirmed by: itchy, atrophic patches of skin in the genital area.

  • Finalized by the predictable outcome of management, e.g. moderate to potent local skin steroid cream.

Lichen simplex chronicus

  • Suggested by: history of habitual rubbing or scratching associated with stress and typically in Asian or Chinese patient.

  • Confirmed by: presence of a single plaque on the back of the neck or in the perineum.

  • Finalized by the predictable outcome of management, e.g. emollients and topical steroids.

Pellagra associated with carcinoid syndrome or anti-TB drugs.

  • Suggested by: diarrhoea, dementia, and dermatitis. May be history of associated condition.

  • Confirmed by: response to nicotinic acid treatment.

  • Finalized by the predictable outcome of management, e.g. correction of fluid and electrolyte imbalance + nicotinamide.

Polymorphic light eruption

  • Suggested by: recurrent lesions on exposure typically in a female.

  • Confirmed by: presence of an eruption, which may range from a few inflamed papules to severely inflamed and oedematous skin.

  • Finalized by the predictable outcome of management, e.g. avoid exposure to sun, use of sunscreens, topical and/or systemic steroids for the acute rash.

Pompholyx

  • Suggested by: history of atopy, stress, allergic reactions to fungal infections elsewhere.

  • Confirmed by: presence of persistent, itchy, clear blisters on fingers and sometimes palms.

  • Finalized by the predictable outcome of management, e.g. symptomatic with antihistamines, antibiotics, and local creams.

Itch with wheals

Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Chronic idiopathic urticaria

  • Suggested by: recurrent nature and by the appearance of wheals variable in size, shape, and number anywhere on skin with no obvious triggering factors.

  • Confirmed by: disappearance of wheals in <24h and possible spontaneous resolution after 6mo.

  • Finalized by the predictable outcome of management, e.g. cetirizine and systemic steroids for severe cases, anaphylactic shock treated with adrenaline and as per protocol in BNF

Acute urticaria

  • Suggested by: sudden urticarial rash after the introduction of the known offending agent, e.g. eggs, fish, peanuts, antibiotics, or latex.

  • Confirmed by: improvement after eliminating the offending agent.

  • Finalized by the predictable outcome of management, e.g. avoiding the offending agent, cetirizine and systemic steroids for severe cases, anaphylactic shock treated with adrenaline and as per protocol in BNF.

Physical urticaria

  • Suggested by: appearance of wheals after exposure to cold, sun, pressure water, and stress.

  • Confirmed by: dermographism and improvement when excluding the offending agent.

  • Finalized by the predictable outcome of management, e.g. avoiding the offending agents for the acute condition; cetirizine or fexofenadine, and systemic steroid for more severe reaction. Adrenaline for anaphylaxis and as per BNF protocol.

Hereditary angioedema

  • Suggested by: +ve FH and an onset from childhood of episodes of angioedema affecting the larynx, impairing respiration and GI system, causing abdominal pain, and vomiting.

  • Confirmed by: low levels of C1-esterase inhibitor and complement studies during the acute episode.

  • Finalized by the predictable outcome of management, e.g. as for urticaria plus IV infusion of C1-esterase inhibitor.

Linear IgA disease

  • Suggested by: blisters and urticarial rash on back and extensor surfaces.

  • Confirmed by: direct immunofluorescence studies revealing linear IgA at basement membrane.

  • Finalized by the predictable outcome of management, e.g. symptomatic treatment

Itch with no skin lesion

Initial investigations (other tests in bold below): digital photography of lesion. FBC, U&E, LFT.

Main differential diagnoses and typical outline evidence, etc.

Chronic liver disease

  • Suggested by: jaundice, spider naevi, enlarged liver.

  • Confirmed by: LFT: ↑bilirubin and ↑alkaline phosphatase, prolonged prothrombin time, and low albumin.

  • Finalized by the predictable outcome of management, e.g. colestyramine.

Chronic renal failure

  • Suggested by: dry, sallow skin itching.

  • Confirmed by:urea and creatinine, and ↓Hb.

  • Finalized by the predictable outcome of management: dietary advice; salt and water management. Regular follow-up. When advanced, plan dialysis or renal transplant.

Iron deficiency

  • Suggested by: pale complexion and skin, koilonychias, angular stomatitis.

  • Confirmed by:Hb, ↓MCV, and ↓ferritin.

  • Finalized by the predictable outcome of management iron replacement, e.g. ferrous sulfate; improvement after treating underlying causes.

Hyperhidrosis

  • Suggested by: excessive sweating, itching, obesity.

  • Confirmed by: typical features and no other features on follow-up.

  • Finalized by the predictable outcome of management, e.g. topical aluminium chloride; if intractable, sympathectomy.

1° hypothyroidism

  • Suggested by: dry skin, fatigue, slow-relaxing ankle jerk.

  • Confirmed by:TSH, ↓T4.

  • Finalized by the predictable outcome of management, e.g. thyroxine replacement.

Lymphoma (Hodgkin’s or non-Hodgkin’s)

  • Suggested by: loss of weight, night sweats, lymphadenopathy, hepatosplenomegaly.

  • Confirmed by: biopsy: Reed–Sternberg cells in Hodgkin’s, not in non-Hodgkin’s lymphoma, etc.

  • Finalized by the predictable outcome of management, e.g. specialist confirmation of diagnosis and staging.

Malignancy

  • Suggested by: general ill health, loss of weight, hepatomegaly, clubbing of fingers, shadow in a CXR.

  • Confirmed by: CT scan of suspect organ(s).

  • Finalized by the predictable outcome of management, e.g. specialists confirmation of diagnosis, staging, and selection for potentially curative or palliative care.

1° biliary cirrhosis

  • Suggested by: non-tender hepatomegaly and splenomegaly, xanthoma, arthralgia, abnormal LFT.

  • Confirmed by: +ve anti-mitochondrial, US examination and liver biopsy.

  • Finalized by the predictable outcome of management, e.g. colestyramine; ursodeoxycholic acid (may increase life expectancy and avoid transplant).

Skin ulceration

Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Staphylococcal infection

  • Suggested by: thin-walled blisters, rupturing easily to leave a yellow, crusted area spreading rapidly, usually on face.

  • Confirmed by: above typical appearance and site.

  • Finalized by the predictable outcome of management, e.g. systemic antibiotic, avoiding local antibiotic due to risk of bacterial resistance.

Basal cell carcinoma

  • Suggested by: small, pearly nodule progressing to central necrosis, producing a crusted ulcer with a rolled edge or a large plaque with a central depression.

  • Confirmed by: histology.

  • Finalized by the predictable outcome of management, e.g. excision.

Squamous cell carcinoma

  • Suggested by: persistently ulcerated or crusted, firm, irregular lesion, usually on sun-exposed areas, e.g. ears, back of hands, bald scalp; in pipe smokers, and patients with leg ulcers.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. excision.

Dermatomyositis

  • Suggested by: purple (heliotrope) rash on eyelid/face, Gottron's papules, muscle weakness.

  • Confirmed by: +ve auto-antibodies, skin and muscle biopsy.

  • Finalized by the predictable outcome of management, e.g. systemic steroids.

Pyoderma gangrenosum

  • Suggested by: recurring nodule, pustular ulcers, about 10cm wide, with a tender, red, necrotic edge, healing with pitted scars on legs, abdomen, and face.

  • Confirmed by: dramatic response to dapsone.

  • Finalized by the predictable outcome of management, e.g. saline cleansing and dapsone.

Rheumatoid arthritis with vasculitis

  • Suggested by: vasculitic ulcer ± purpura, swollen and deformed phalyngeal joints with ulnar deviation. Rheumatoid nodules.

  • Confirmed by: +ve rheumatoid factor, erosive appearance on joint X-ray.

  • Finalized by the predictable outcome of management, e.g. NSAIDs, steroids, disease-modifying drugs, skin grafting.

Syphilis

  • Suggested by: an isolated, painless genital ulcer (primary chancre).

  • Confirmed by: serology, histology and typical appearance.

  • Finalized by the predictable outcome of management, e.g. benzylpenicillin.

SLE

  • Suggested by: associated facial butterfly rash, photosensitivity (face, dorsum of hands, neck), red scaly rashes.

  • Confirmed by: +ve and high titre antinuclear auto-antibodies, immunofluorescence studies.

  • Finalized by the predictable outcome of management, e.g. symptomatic treatment, systemic steroids.

Wegener’s granuloma

  • Suggested by: skin and mouth ulcers, nasal ulceration with epistaxis, cranial nerve lesions, haemoptysis.

  • Confirmed by: cANCA +ve. Biopsy showing granulomatous vasculitis.

  • Finalized by the predictable outcome of management, e.g. high-dose systemic steroids.

Photosensitive rash

The initial management of all these conditions will clearly involve avoidance of exposure to sunlight and use of sunblock creams. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Polymorphic light eruptions

  • Suggested by: recurrent rash on exposure to sun, typically in a female patient.

  • Confirmed by: presence of an eruption, which may range from a few inflamed papules to severely inflamed and oedematous skin.

  • Finalized by the predictable outcome of management, e.g. improvement by avoiding the exposure to sun, use of sunscreen. Topical and/or systemic steroids for the acute rash.

Plant chemical hyperphotosensitivity

  • Suggested by: red-brown macules on arms, hands, and face (blistering first) after exposure to sunlight.

  • Confirmed by: history of cutting plants (e.g. giant hogweed) without skin covering.

  • Finalized by the predictable outcome of management, e.g. sunblock and avoidance of exposure to sun. Cosmetics to conceal pigmentation.

Actinic prurigo

  • Suggested by: presence since childhood with papules appearing on sun-exposed sites.

  • Confirmed by: improvement after protecting the exposed site.

  • Finalized by the predictable outcome of management, e.g. sunblock and avoidance of exposure to sun. Cosmetics to conceal pigmentation.

Drug-induced photosensitivity

  • Suggested by: intake of a drug or the application of a cream that are known to cause photosensitivity, e.g. amiodarone, furosemide, tetracycline, and sunscreen agents.

  • Confirmed by: improvement after eliminating the offending agent.

  • Finalized by the predictable outcome of management, e.g. emollients and steroid creams, and avoidance of exposure to sun.

Pellagra associated with carcinoid syndrome or anti-TB drugs

  • Suggested by: diarrhoea, dementia, and dermatitis. History of predisposing condition.

  • Confirmed by: response to treatment with nicotinic acid.

  • Finalized by the predictable outcome of management, e.g. correction of fluid and electrolyte imbalance + nicotinamide.

  • Solar urticaria

  • Idiopathic or drug-induced, e.g. aspirin or opiates

  • Suggested by: urticarial rash appearing after exposure to sun.

  • Confirmed by: no other features on follow-up.

  • Finalized by the predictable outcome of management, e.g. avoidance of sun exposure, and use of cetirizine and local emollients.

SLE

  • Suggested by: facial butterfly rash, photosensitivity (face, dorsum of hands, neck), red scaly rashes.

  • Confirmed by: +ve and high titre antinuclear auto-antibodies. Direct skin immunoflorescence studies.

  • Finalized by the predictable outcome of management, e.g. improvement by avoiding exposure to sun, systemic steroids.

Subacute cutaneous lupus erythematosus

  • Suggested by: symmetrical, scaly plaques on sun-exposed areas of face and forearm.

  • Confirmed by: presence of anti-Ro antibodies. Biopsy.

  • Finalized by the predictable outcome of management, e.g. avoid exposure to sun and use sunscreen. Local steroid creams.

Pemphigus associated with autoimmune thyroiditis, hypothyroidism or myasthenia gravis

  • Suggested by: presence of superficial blisters on the scalp, face, back, chest, and flexures ± preceding mouth erosions. History of other autoimmune disease.

  • Confirmed by: IgG autoantibodies to epidermal components. Direct immunofluoresence studies showing deposition of IgG antibodies.

  • Finalized by the predictable outcome of management, e.g. avoid exposure to sun. High dose of prednisolone orally with or without azathioprine or cyclophosphamide.

Pigmented moles

A flat or raised pigmented spot in the skin. Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Blue melanocytic naevus

  • Suggested by: solitary with colour commonly on hands and feet.

  • Confirmed by: above appearance with no change on follow-up over weeks to months. Biopsy, if in doubt.

  • Finalized by the predictable outcome of management, e.g. no changes over time.

Spitz melanocytic naevus

  • Suggested by: fleshy, firm, reddish-brown, round papule or nodule, usually on face or leg of a child.

  • Confirmed by: above appearance with no change on follow-up over weeks to months.

  • Finalized by the predictable outcome of management, e.g. no changes over time.

Halo melanocytic naevus

  • Suggested by: presence of a white halo of depigmentation surrounding the original naevus, usually on trunk of a child or an adolescent. May be history of vitiligo.

  • Confirmed by: above appearance with no change on follow-up over weeks to months.

  • Finalized by the predictable outcome of management, e.g. no changes over time.

Becker’s melanocytic naevus

  • Suggested by: large, hairy, pigmented area. Present unilaterally in an adolescent male on the upper back, shoulders, or chest.

  • Confirmed by: above appearance with no change on follow-up over weeks to months.

  • Finalized by the predictable outcome of management, e.g. same appearance over time.

Freckles

  • Suggested by: presence of small, pigmented macules <5mm in diameter on sun-exposed area of a fair-skinned person.

  • Confirmed by: above appearance with no change on follow-up over weeks to months.

  • Finalized by the predictable outcome of management, e.g. no changes over time.

Seborrhoeic wart

  • Suggested by: presence of round or oval pigmented spot on the trunk or face in an elderly or middle-aged person. Progression from small papule into a pigmented warty nodule.

  • Confirmed by: ‘stuck-on’ appearance and multiplicity of lesions.

  • Finalized by the predictable outcome of management, e.g. cryotherapy, curettage, or shave biopsy.

Chloasma

  • Suggested by: appearance of large (<5mm) areas of pigmentation during pregnancy.

  • Confirmed by: resolution in months following delivery.

  • Finalized by the predictable outcome of management, e.g. sunscreens and camouflage cosmetics.

  • Peutz–Jegher’s syndrome

  • (with risk of colonic and other neoplasms)

  • Suggested by: small (<5mm) macules on the lips, in the mouth, and around the eyes and nose; also around the anus, hands, and feet. Present since infancy or childhood and fade with age.

  • Confirmed by: presence of polyposis coli on colonoscopy.

  • No treatment but refer for regular colonoscopy to remove suspicious polyps.

Dysplastic naevi

  • Suggested by: irregular outline and deep pigmentation.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. surgical excision.

Malignant melanoma ‘superficial spreading’, ‘lentigo’, ‘acral lentiginous’, ‘nodular’

  • Suggested by: recent increase in the size of a naevus, irregular outline, variation of colour, itchiness, and oozing or bleeding. ‘Superficial spreading’ (up to 50%, typically on leg, female), ‘lentigo’ (up to 50%); acral lentiginous (10%) on palms, soles, and nailbed of dark-skin); ‘nodular’ (25%, typically on trunk).

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. dermatologists confirmation of diagnosis and surgical intervention. Prognosis is related to tumour thickness: 5-y survival rate: <1mm=95%; 1–2mm=90%; 2.1–4mm=77%; >4mm=65%.

A tumour on the skin

Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Seborrhoeic wart

  • Suggested by: a round or oval pigmented spot on the trunk or face in an elderly or middle-aged person, starting as a small papule, progressing to a pigmented warty nodule.

  • Confirmed by: ‘stuck-on’ appearance and multiplicity of lesions.

  • Finalized by the predictable outcome of management, e.g. cryotherapy, curettage, or shave biopsy.

Epidermal cyst

  • Suggested by: a cystic swelling on scalp, face, or trunk, with a firm consistency and skin-coloured.

  • Confirmed by: typical appearance and little progression over weeks to months.

  • Finalized by the predictable outcome of management, e.g. excision.

Milium

  • Suggested by: small, white cysts around the eyelids and on the cheeks, usually seen in children.

  • Confirmed by: typical appearance.

  • Finalized by the predictable outcome of management, e.g. extraction by a sterile needle.

Dermatofibroma

  • Suggested by: a nodular lesion in a young adult, typically on the lower leg of a female.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. excision.

Pyogenic granuloma

  • Suggested by: a rapidly growing, easily bleeding, bright red, and may be pedunculated nodule, usually on a finger.

  • Confirmed by: excisional biopsy.

  • Finalized by the predictable outcome of management, e.g. excision.

Keloid

  • Suggested by: irregular and excessive skin growth at the site of a trauma, producing nodules or plaques on the upper back, neck, chest, and ear lobes.

  • Confirmed by: typical appearance with failure to resolve.

  • Finalized by the predictable outcome of management, e.g. steroid injections.

Campbell-de-Morgan spot

  • Suggested by: presence of small red papules on the trunk in elderly.

  • Confirmed by: typical appearance with little change over months.

  • Finalized by the predictable outcome of management, e.g. acceptance or cauterization.

Lipoma

  • Suggested by: soft, subcutaneous, fatty mass, usually multiple, and commonly found on trunk of neck.

  • Confirmed by: above appearance, and slow or no progression over months to years.

  • Finalized by the predictable outcome of management, e.g. excision, if unsightly.

Chondrodermatitis nodularis

  • Suggested by: a painful nodule on the sun-exposed helix of the pinna in elderly.

  • Confirmed by: typical appearance and site.

  • Finalized by the predictable outcome of management, e.g. excision.

Keratoacanthoma

  • Suggested by: a rapidly forming nodule on a sun exposed area. The centre falls leaving a crater.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. excision.

Basal cell carcinoma

  • Suggested by: presence of a nodule, usually started as a papule, developing central necrosis and producing an ulcer with rolled edges, usually on sun-exposed sites, e.g. by the nose and on the temple.

  • Confirmed by: excisional biopsy.

  • Finalized by the predictable outcome of management, e.g. excision.

Squamous cell carcinoma

  • Suggested by: history of chronic sun exposure, pipe smoking, chronic ulceration, e.g. a burn or renal transplant.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. surgical excision.

Malignant melanoma

  • Suggested by: recent increase in the size of itchiness, and oozing or bleeding naevus, irregular outline, variation of colour.

  • Confirmed by: biopsy.

  • Finalized by the predictable outcome of management, e.g. dermatologists confirmation of diagnosis and surgical intervention.

Hyperpigmented skin

Initial investigations (other tests in bold below): digital photography of lesion.

Main differential diagnoses and typical outline evidence, etc.

Freckles

  • Suggested by: brown macules, usually on the face, and become darker on sun exposure.

  • Confirmed by: above appearance and no progression over months to years.

  • Finalized by the predictable outcome of management, e.g. no progression over time.

Lentigines

  • Suggested by: brown macules, not affected by exposure to sun, usually seen in elderly.

  • Confirmed by: above appearance and no progression over months to years.

  • Finalized by the predictable outcome of management, e.g. no changes over time.

Drug-induced

  • Suggested by: intake of a drug, e.g. amiodarone, phenothiazine, minocycline, and oestrogen.

  • Confirmed by: improvement on removing the drug.

  • Finalized by the predictable outcome of management, e.g. eliminate offending agent.

Addison’s disease

  • Suggested by: pigmentation in palmar creases and buccal mucosa. Nausea, weight loss, ↓BP, etc.

  • Confirmed by:ACTH with ↓cortisol, and poor response to Synacthen® stimulation test.

  • Finalized by the predictable outcome of management, e.g. replacement hydrocortisone and fludrocortisone.

Cushing’s disease

  • Suggested by: pigmentation in palmar creases and buccal mucosa.

  • Confirmed by:ACTH with ↑cortisol with failure to suppress normally in dexamethasone test.

  • Finalized by the predictable outcome of management, e.g. metyrapone initially, then plan for pituitary adenectomy.

Biliary cirrhosis

  • Suggested by: non-tender hepatomegaly, splenomegaly, xanthelasmatosis, xanthoma, arthralgia.

  • Confirmed by: +ve anti-mitochondrial antibodies and liver biopsy.

  • Finalized by the predictable outcome of management, e.g. colestyramine.

Pemphigoid

  • Suggested by: presence of tense, large blisters arising on a red or a normal-looking skin, usually in an elderly patient, on the limbs, trunk, and flexures, or mouth.

  • Confirmed by: specific IgG antibodies to the antigens BP230 and BP180, and direct immunofluorescence studies show IgG and C3 antibodies in the subepidermis.

  • Finalized by the predictable outcome of management, e.g. low dose of prednisolone orally ± azathioprine.

Pellagra

  • Suggested by: presence of diarrhoea, dementia, and dermatitis. History of carcinoid syndrome or anti-TB drugs.

  • Confirmed by: response to nicotinic acid.

  • Finalized by the predictable outcome of management, e.g. correction of fluid and electrolyte imbalance + nicotinamide.

Carotenaemia

  • Suggested by: eating many carrots or dye-containing foods.

  • Confirmed by: dietary history and response to advice.

  • Finalized by the predictable outcome of management, e.g. improvement after following a dietary advice.

Lichen planus

  • Suggested by: associated Koebner’s phenomenon.

  • Confirmed by: presence of itchy, well-defined, and raised, shiny-surfaced lesions with a violaceous colour interpreted by white streaks (Wickman’s striae).

  • Finalized by the predictable outcome of management, e.g. topical steroids; systemic steroids for extensive lesions.

Acanthosis nigricans

  • Suggested by: skin thickening and pigmentation.

  • Confirmed by: presence of pigmented, velvety, and papillomatous skin lesion of flexures, neck, nipples, and umbilicus.

  • Finalized by the predictable outcome of management, e.g. treatment of underlying problem, e.g. diabetes mellitus.

Hypopigmented skin

Initial investigations (other tests in bold below): digital photography of lesion.

Vitiligo

  • Suggested by: presence of symmetrical, non-scaly, white macules ± history of injury or sun exposure, usually on hand, neck, and around mouth.

  • Confirmed by: above appearance and little or no change over months or years.

  • Finalized by the predictable outcome of management, e.g. camouflage cosmetics, sunscreens, PUVA.

Albinism

  • Suggested by: FH, white or pink skin, white hair, poor sight.

  • Confirmed by: above appearance and little or no change over months or years.

  • No treatment but advise to avoid sun exposure (risk of cancer).

Phenylketonuria

  • Suggested by: fair skin, learning difficulties.

  • Confirmed by: iphenylalanine in blood.

  • Finalized by the predictable outcome of management, e.g. low phenylalanine diet.