Skin Disease in Perspective

Dermatology is the study of the skin and its associated structures, including the hair and nails, and of their diseases. It is an immense subject, embracing some 2000 conditions, yet, paradoxically, some 70% of the dermatology work in the UK is caused by only nine types of skin disorder (Table 1.1). Similarly, in the USA, nearly half of all visits to dermatologists are for one of three diagnoses: acne, warts and skin tumours. Things are very different in developing countries where overcrowding and poor sanitation play a major part. There, skin disorders are even more common, particularly in the young, but are dominated by infections and infestationsathe so-called ‘dermatoses of poverty’a amplified by the presence of HIV infection. A sense of perspective is important, and this chapter presents an overview of the causes, prevalence and impact of skin disease. Causes The skin is the boundary between ourselves and the world around us. It is an important sense organ, and controls heat and water loss. It reflects internal changes 1 Skin disease in perspective Table 1.1The most common categories of skin disorder in the UK. Skin cancer
Acne
Atopic eczema
Psoriasis
Viral warts
Other infective skin disorders
Benign tumours and vascular lesions
Leg ulcers
Contact dermatitis and other eczemas