EXPERIMENTAL MILIARIA IN MAN I. Pouci'io OF SWEAT RETENTION ANIDROSIs AND VESICLES BY MEANS OF IONTOPHORESIS*t

Sweat retention due to obstruction of the sweat duct in the presence of functioning glandular acini plays a pr mary role in miliaria crystallina (1, 2) miliaria rubra (3, 4) tropical anidrosis (4, 5, 6) Fox-Fordyce disease (7), and hidrocystoma (8, 9). In addition, sweat duct obstruction may occur secondarily in ichthyosis, atopic dermatitis and in seborrheic dermatitis (10). It might be expected to occur in granulosis rubra nasi, certain types of chronic vesicular eruption of the palms and soles, contact dermatitis, and acrodynia. The effect of many popular local anidrotics is achieved through the production of a closure of the sweat duct orifice (ii). With the recent clear definition of the sweat blockage factor (10) there has come a need for further studies on the pathogenesis which attends primary closure of the excretory channel of the sweat gland. Many theories have been advanced as to the etiology of this functional obstruction. In the case of miliaria, Haight (12) suggested that a simple mechanical closure of the spiraling intraepidermal duct resulted from the pressure of an excessive volume of sweat. Pollitzer (12) explained the closure as due to an abnormal increase in the imbibition of sweat by the stratum corneum, with resultant blockage at the duct orifice by these enlarged cells. He reasoned that this degree of imbibition occurred, when excessive lipoid had been lost from the skin surface. To support his hypothesis, he pointed out that the rarity of miliaria on the face could result from the fact that the face is richly supplied with sebum. Sulzberger (3) advanced the hypothesis that profuse sweating leads to maceration of the skin surface, faulty keratinization, occlusion of sweat pores by horny plugs, and the subsequent appearance of miliaria. O'Brien (4) regards miliaria rubra as a manifestation of lipoid deficiency of the skin. He states that this deficiency results from too rapid a removal of sebum by clothing, soap, powder, lotions and alcohol, or by a diminution in the production of sebum. To test his theory, he subjected 20 individuals to artificial lipoid depletion by applying fat solvents. In 15 of the subjects, a dermatitis appeared which resembled miliaria rubra both clinically and histopathologically. Unfortunately, no details of the method were given. This, however, is the solitary report of an experimental production of miliaria.