The Photosensitive Patient: Could It Be Pellagra?

The commentary discusses the often overlooked diagnosis of pellagra, a condition caused by niacin deficiency, which presents with a classic triad of symptoms: dermatitis, diarrhea, and dementia. However, in developed nations where pellagra is rare, patients may present with only photosensitivity and hyperpigmented plaques on sun-exposed skin, which can be mistaken for other dermatological conditions. The article by Wan et al. in the same issue of the British Journal of Dermatology provides a comprehensive review of pellagra, emphasizing the importance of considering this diagnosis in photosensitive patients, especially those with risk factors such as excessive alcohol intake, eating disorders, or underlying gastrointestinal diseases. The review also notes that certain medications can predispose patients to pellagra. Diagnosis is confirmed by low serum niacin levels and the condition responds well to oral niacin supplementation. The commentary underscores the need for further study to better understand pellagra, including its action spectrum and whether its photosensitivity is a primary or secondary feature.