In the early descriptions observers expressed the belief that pellagra was caused by the sun, and it was accordingly designated by many writers as mal de la sol or sickness of the sun.1 Since that time various writers have held that sunlight was either the sole cause or a major factor in the pathogenesis of the disease. Bass,2 Ormsby,3 Sutton4 and Ruffin and Smith5 described the development of pellagrous erythema in pellagrins exposed to direct sunlight. Some writers believed that the pellagra-producing portion of the sunlight is present in the violet end of the spectrum.6 All these conclusions have, of necessity, been based on personal interpretations, at times without full regard for the inherent difficulties in distinguishing between the erythema of sunburn and that of pellagra.
The present study is concerned with observations on pellagrous dermatitis and the relationship of these cutaneous changes to exposure
SPIES TD. RELATIONSHIP OF PELLAGROUS DERMATITIS TO SUNLIGHT. Arch Intern Med (Chic). 1935;56(5):920-926. doi:10.1001/archinte.1935.00170030088009