Nails and hair

The hair and nail are appendages of the skin. They both hang off it and are part of it. Their growth, condition and integrity are indicators of both local and systemic pathologies. Age results in significant changes in hair growth with characteristic patterns of baldness evolving with time. Excess hair is largely a complaint of women, in whom it may represent part of the normal spectrum of pigmented coarse hairs in a male distribution or be a sign of an endocrine pathology. The most common diseases causing disturbance of the nail are inflammatory diseases of the skin, such as psoriasis and eczema. These can also cause problems on the scalp, although the scarring skin diseases such as discoid lupus erythematosus and lichen planus are of additional significance at this site. Some inflammatory diseases, such as alopecia areata, are specific to the hair follicle and matrix of the nail. Bacterial and fungal infections can affect the skin within which the appendage is lodged, or invade the appendage itself, providing characteristic patterns of disease. Malignancy is relatively uncommon, but this rarity also means that there is often significant delay in diagnosis, which in the case of subungual malignant melanoma can result in very poor prognosis.