Caption

Lichen planus lesions on a patient's arm. This skin disease is characterised by rounded, coloured skin eruptions with thickening of the surrounding skin. The cause of lichen planus is obscure. In some cases it may be of nervous or emotional origin, but in others it may be due to drugs. Some diuretics and antimalarials have been suggested as possible causes. Treatment is with topical corticosteroids and with antihistamines to reduce itching. Most cases of lichen planus heal within two years. Photographed in Africa.