Skin disorder caused by niacin (vitamin B group) deficiency. The skin abnormality is associated with diarrhoea. The skin of the entire body is covered with sharply defined, scaly, red patches, followed by inflammation of the skin. The vitamin occurs in numerous foodstuffs, including green vegetables, cereals, fruit and meat. The condition is rare in the West. Treatment is with B- complex vitamin tablets or by injections if there is intestinal disturbance.