While miliaria is not uncommon in a hot and humid climate, a special predisposition to its development has long been considered important. This point was emphasized recently by Shelley and Horvath1 in their work on experimental miliaria. They found that miliaria crystallina could be produced routinely in normal subjects by various types of epidermal injury. On the contrary, miliaria rubra was induced in only 1 of 10 of these subjects, while it was produced invariably in 10 subjects who previously had had some form of prickly heat. The nature of this predisposition was not determined. Shelley and Horvath speculated that it might be related to the structure and permeability of the sweat duct wall.
Recently, a patient who had had recurrent attacks of clinically typical miliaria rubra was seen, and special studies were made. The patient, a 23-year-old white woman, had been bothered with showers