A 47-year-old man, with no medical history, presented with a 1-year history of a recurrent skin eruption made of erythematous, erosive, crusty and pruritic plaques involving the scrotum, inguinal and intergluteal skinfolds, trunk and legs (figure 1). Mucosal examination showed glossitis and perleche. He had received topical and systemic antifungal agents without improvement. General examination was normal except a weight loss of 9 kg, without other digestive symptoms and despite a balanced diet. Blood routine tests were normal except a mild normocytic anaemia (11 g/dL) and a hypoalbuminaemia (31 g/L). Nutritional assessment revealed a zinc deficiency (7.37 µmol/L, normal value >12.5 µmol/L). Histological examination of a …