Pellagra may be a rare secondary complication of anorexia nervosa: a systematic review of the literature.

Pellagra is a nutritional wasting disease attributable to a combined deficiency of tryptophan and niacin (nicotinic acid). It is characterized clinically by four classic symptoms often referred to as the four Ds: diarrhea, dermatitis, dementia, and death. Prior to the development of these symptoms, other nonspecific symptoms insidiously manifest and mostly affect the dermatological, neuropsychiatric, and gastrointestinal systems. A review of the literature reveals several case reports describing pellagra in patients with anorexia nervosa. The most common features of pellagra in patients with anorexia nervosa are cutaneous manifestations such as erythema on sun-exposed areas, glossitis, and stomatitis. Health care providers might consider a trial of 150-500 mg niacin if anorexic patients exhibit these cutaneous findings. Pellagra can be diagnosed if cutaneous symptoms resolve within 24-48 hours after oral niacin administration. To further corroborate a diagnosis of pellagra in anorexic patients, specific 24-hour urine tests for niacin metabolites and 5-hydroxy-indole-acetic acid could be run prior to treatment with niacin being instituted. Other factors, such as mycotoxins, excessive dietary leucine intake (although not in anorexia), estrogens and progestogens, carcinoid syndrome, and various medications, might also lead to the development of pellagra. Although pellagra appears to be a rare, yet possible secondary complication of anorexia nervosa, it should be considered in the work-up of patients who exhibit cutaneous manifestations subsequent to sunlight exposure.