Mechanisms of eccrine anidrosis. I. High level blockade.

The cause of anidrosis of the chronic dermatoses, hydration, and that produced experimentally by protein precipitants is superficial obstruction of the eccrine duct. In each instance, return of sweating in the anidrotic area is effected simply by removal of the stratum corneum with Scotch Tape stripping. The histologic picture common to this type of anidrosis is ductal dilatation following an adequate sweat stress. The presence of an obstruction, whether functional or anatomic, is confirmed by the inability to achieve a methylene blue pore pattern. Parakeratotic plugging of the eccrine ostia is primarily responsible for the obstruction in the spontaneous dermatoses, while actual intraluminal casts are produced chemically by the protein denaturants, high within the stratum corneum portion of the eccrine duct. The PAS positive, diastase resistant casts regularly found in blocked ducts are secondary to the obstruction and are not a primary cause. No adequate explanation has been found for the persistent anidrosis after occlusion of the skin with impermeable plastic dressings.