5.11.1. Introduction

Diseases of the skin, the largest organ in the body with vital social functions.

are very common in Europe affecting, about one-quarter to one-third of all the population. With the exception of melanoma skin cancer, most skin diseases are not life threatening. Relatively minor skin complaints often cause more anguish to people than other more serious medical disorders. The high prevalence of skin disease and the variety of associated symptoms result in a large burden of disease in global terms.

The skin is a sensitive dynamic boundary between ourselves and the outside world. Its functions include defence against infections and infestations, protection against irritants, ultraviolet radiation and trauma. The skin is essential for controlling water and heat loss of the body and is an important sensory organ which distinguishes pain, touch, itching, heat and cold. Vitamin D is synthesized in the skin. The skin is also an important organ of social and sexual contact. Perhaps the greatest disability of all is to be unwelcome and to have no confidence in one’s appearance. In addition to the epidermis and dermis, the skin contains other structures including nails, hair, blood vessels, nerves, sweat and sebaceous glands, all of which can become involved separately or combined to produce a wide range of skin diseases. The skin also has a crucial and frequently underestimated social function.

Historically there has been a tendency to trivialize skin disease within the medical profession and give it a low priority in research programmes. However, the public and those involved in primary care have a very different point of view. The psychological effects of relatively minor skin complaints can often cause more distress to the public than other more serious medical disorders (Ryan et al, 1991).

Unlike most other medical specialties which usually cite around 50 diseases, dermatology has a complement of between 2000 to 3000 conditions. However, less than 10 skin disease groups probably account for 70% of dermatological consultations (Williams, 1997). Most of the major systemic diseases (e.g. infectious, vascular and connective tissue diseases) have manifestations which frequently affect the skin and, conversely, skin failure (e.g. caused by a severe drug reaction) has many systemic effects ranging from dehydration to heart failure, septicaemia and death.

Skin disease which benefits from medical care is very common, affecting around 22.5–33.0% of the European population (Rea et al, 1976; Johnson, 1978).

Despite the magnitude of skin disease morbidity in the general population, research on such pathologies has been relatively minor.