The prevalence of alcohol abuse in the general population is often underestimated. The skin has the advantage of being directly visible and can therefore be examined easily. Awareness of the cutaneous conditions associated with alcohol abuse can help physicians identify patients at risk. Skin diseases such as psoriasis, discoid eczema and porphyria cutanea tarda merit particular attention as they may occur earlier than the classical signs of liver disease, which are well known in alcoholics.

The most widely recognised signs are palmar erythema, spider naevi and nail changes.

All of these changes appear to have a vascular origin and are more often observed on the upper part of the body than on the lower body.

Facial redness (flushing) is a common result of alcoholism. Orientals are more sensitive to facial flushing. Persistent facial erythema is thought to be due to chronic vasodilation and loss of vasoregulatory control mechanisms. Fine dilation of a group of capillaries is characteristic and can occur in conjunction with persistent acne. Affected individuals are usually alcohol abusers rather than alcoholics.

Autonomic neuropathy may develop in chronic alcoholism; in advanced disease, sympathetic neuropathy may result in distal sweating, exaggerating the feeling of warmth on the palms.

Alcohol intoxication frequently leads to repeated and often unexplained trauma, and multiple ecchymoses (extravasation of blood into subcutaneous tissue) may result. This tendency to bruising may be increased by abnormalities in platelet function induced by alcohol abuse.

Pellagra (photosensitivity induced by nicotinic acid) and scurvy (disseminated perifollicular haemorrhages, stomatitis, cork-screw hairs and ecchymoses) can occur in chronic alcoholism, as a result of vitamin deficiency.

Acne rosacea is characterised by prominent erythema, telangiectasis and pustule formation, with accompanying vasomotor instability. It occurs most frequently in the middle of the face but can also affect other parts of the body. Concomitant tissue hypertrophy can result in rhinophyma.

Porphyria cutanea tarda is the commonest form of porphyria (a metabolic defect characterised by elevated blood porphyrin levels) and may be familial or acquired. It is caused by a block in the biosynthetic pathway of haemoglobin at the level of uroporphyrinogen carboxylase. The resulting accumulation of uroporphyrin induces photosensitivity.

Discoid eczema is characterised by well-circumscribed, nummular (coin-shaped) plaques of dermatitis, which are usually observed on the lower legs. This form of eczema is very resistant to treatment.