Pellagra is a nutrient deficiency disease caused by insufficient niacin levels. Recent studies have shown that numbers of epidermal Langerhans cells decreased in other diseases caused by nutritional deficiencies, including necrolytic migratory erythema and acrodermatitis enteropathica. Epidermal Langerhans cells are capable of modulating or even halting the inflammatory reaction. The aim of this study was to examine changes in the number of Langerhans cells and other dendritic cells, and maturation of epidermal Langerhans cells in the lesional and adjacent non-lesional skin in pellagra patients. Seven pellagra patients and 10 healthy individuals who served as controls were included. The number and distribution of dendritic cells and other cutaneous cells were examined by immunohistochemistry. Epidermal Langerhans cells decreased considerably in the skin lesions of pellagra patients, whereas other dendritic cells did not change. The decrease in the number of Langerhans cells was positively correlated with the histological severity of skin lesions. As the number of Langerhans cells was not reduced in the undisturbed neighboring skin, the depletion of epidermal Langerhans cells did not precede skin damage but was a cause of prolonged severe inflammation.