Dermatology is a fascinating subject. This is a statement you might expect from a dermatologist, but what is the justification? It is a highly clinical specialty and sophisticated techniques of diagnosis are very much of secondary importance compared with clinical skills. The skin is important not only as an organ with vital physiological functions but also as a flag by which we communicate with the outside world. A perfect skin is desired by all, and upon this wish is based the multi-million pound cosmetics industry. Skin disease therefore places a strain on sufferers out of proportion to the disturbances in function which the pathology produces. A "leper" complex is frequent, and social and sexual contact may be shunned because of the embarrassment caused. It is also easy to overlook the contribution that cutaneous physical signs make towards diagnoses of internal disorders. Even straightforward factors such as the pallor of anaemia, the icterus of biliary obstruction or, quite simply, the age and sex of the patient are recognised immediately from visible signs in the skin. Like most other organs the skin has a limited repertoire of reactions, but these can occur in patients of all ages, combined together in an almost infinite number of permutations; hence the fascination referred to above. It has been estimated that 10% of consultations with general practioners are because of a skin-related problem, and therefore a working knowledge of dermatology is essential for anyone who has regular clinical contact with patients.