Definition. A non-inflammatory, obstructive condition of the sweat-glands, showing small clear vesicles and usually appearing during the course of a febrile disease.
Symptoms. Numerous, discrete, pin-head, transparent vesicles, appearing upon the abdomen or chest, although they may appear anywhere, describes the eruption. The lesions appear rapidly in a few hours, rupture spontaneously in a few days and soon leave the skin clear unless fresh crops appear. The color of the skin is unchanged about the lesions which may be few or many. They produce no subjective symptoms, and often occur during the so-called “critical” sweating of typhoid, typhus, rheumatic, puerperal and hectic fevers.
Etiology and Pathology. The presence of some acute systemic disturbance which diminishes both the nutrition of the skin and the sweat is probably the first cause of sudamen. The retained or changed epithelium blocks up the orifice of the sweat-ducts while the skin is dry so that a sudden resumption of sweat formation, unable to escape by the natural outlet, forms a sweat vesicle underneath the horny cells of the epidermis.
Diagnosis. The dewdrop-like vesicle, absence of local signs of inflammation and occurrence in the course of a fever cannot be mistaken for any other eruption. Miliaria and vesicular eczema are inflammatory. Hydrocystoma is located on the face and lacks the febrile element.
Prognosis and Treatment. This condition only lasts a few days although there may be recurrent crops. The nature of the affection suggests such remedies as Am. mur., Bryonia, Hydrocot., Mercurius viv. and Urtica urens, but usually it is not treated specifically. The parts may be sponged with dilute alcohol and then a simple dusting powder applied.