Pigmentation of the Black Skin in Health and Disease

Abstract

Appearing in this issue of the Journal are two articles which deal with pigmentation abnormalities of the black skin. This editorial comment is designed [0 provide some background information, and thereby facilitate understanding and appreciation of the two articles by all readers. 1be colour of human skin is due predominantly to the presence of the biological brownish black. pigment melanin in the epidermis. Other pigments such as carotenoids (yellow), oxyhaemoglobin (red), reduced haemoglobin (blue) which play relatively insignificant roles when melanin pigmentation is heavy, assume some significance in individuals who lack melanin completely. such as albinos, or have very little of it., (very fair Caucasians) in whom the skin assumes a pink colour. For practical purposes therefore. human skin pigmentation means melanin pigmentation. the function of melanin is protection of the individual against the harmful effects of ultraviolet light. Light is essential for vital biological functions such as Vitamin 0 synthesis and vision, however the Ultra-Violet B (UVB) pan of the spectrum (wavelength 290-32Onm) is capable of destroying tissue leading to sunburn, premature ageing and neoplastic degeneration