Pellagra-Fine arts and literature: A short journey from Pietro Belloti and Johann Wolfgang Goethe to John Wesley Caroll and Amedeo John Engel Terzi.

Pellagra is a non-hereditary disorder of the niacin and tryptophan metabolism. Cutaneous and gastrointestinal signs and symptoms are early signs of the disease, but neuropsychiatric findings follow, if the disease is not recognized and treated soon enough. Although pellagra had not been identified as a separate entity before 1735, artists noticed the characteristic cutaneous manifestations. An example is Pietro Bellotti's masterpiece Vecchia popolana con un ragazzo (Old Peasant Woman with a Boy; ca 1680-1690) with a most realistic style. In 1786, the German writer and scientist Goethe traveled to Northern Italy. In his book Italienische Reise (Italian Journey), he made remarks about cutaneous findings in the rural population suggesting pellagra. He missed the scaling and fissuring of skin, as he traveled in the autumn and not spring, when the disease has its seasonal peak. The association of pellagra with art is further illustrated by two examples of the early 20th century-painter John Wesley Carroll from Kansas and medical illustrator Amedeo John Engel Terzi from Sicily. Their multicolored illustrations supported education about the disease before high-quality color photography became available.