MODEL RELEASED. Vitamin B3 deficiency. Cracked and inflamed skin (light patches) on a child's face, a symptom that the child's diet is deficient in vitamin B3. This disorder is known as pellagra. Other pellagra symptoms are an upset digestive system, diarrhoea and depression. Vitamin B3 exists in two forms: niacinamide and niacin. One of the complex of B vitamins, it takes part in many metabolic reactions and, like other vitamins, is needed only in small amounts, but is an essential part of a healthy diet. Good sources of vitamin B3 are liver meat, groundnuts and seeds from the sunflower plant. Photographed in Africa.