This dermatology handbook is written for core medical trainees, dermatology trainees, and dermatology consultants, but it includes much that will be of value to those working in the community and to medical students who want to know more about the skin. The focus is on medical management, rather than surgical dermatology, i.e. no surgical techniques/procedures. We provide a framework for analysing clinical signs, so that you can develop your diagnostic expertise, and a practical approach to management with answers to questions such as ‘What should I ask?’, ‘What should I look for?’, or ‘What should I do?’. The content has been thoroughly revised and updated with a new chapter on genodermatoses, as well as expanded chapters devoted to cutaneous tumours, cutaneous adverse drug reactions (including new chemotherapeutic agents), paediatrics (including paediatric vascular malformations), and rheumatology (new classification criteria for cutaneous lupus erythematosus). We discuss common or important conditions (and some fascinating rarities), including skin infections and infestations, inflammatory dermatoses (e.g. psoriasis, eczema, acne, urticaria), blistering diseases, oral and genital ulcers, skin tumours, vasculitis, lymphoedema, and leg ulcers. The section on emergency dermatology will help you to recognize and manage life-threatening problems such as angio-oedema, toxic epidermal necrolysis, and purpura fulminans. The chapters on skin problems in medical specialties should be of particular interest to trainees working in a variety of areas—we discuss the approach to skin conditions that you may encounter in paediatrics, rheumatology, haematology, nephrology, endocrinology, gastroenterology, respiratory medicine, obstetrics, geriatrics, neurology, and psychiatry.