[Pellagra secondary to chronic alcoholism in Costa Rica].

Introduction: pellagra is a disease caused by a deficiency of niacin (vitamin B3) or tryptophan, its precursor. Case report: we present the case of a 67-year-old Costa Rican male patient, alcoholic and homeless, with chronic ulcers on the lower limbs, photosensitive dermatitis, gait disturbance, mild cognitive impairment, and dysthymia. A diagnosis of pellagra was made based on clinical findings, which was later confirmed by a positive response to vitamin supplementation. Discussion: a review of pellagra, a condition that is increasingly underdiagnosed, was conducted; in this case, it presented with 2 of the 3 classic manifestations described in the literature.