Diseases of Sweat Glands

The basic mechanisms of sweat gland function and an updated review of some relatively common disorders of sweat secretion, are presented. Although sweat secretion and ductal absorption are basically biophysical and biologic cellular processes, a detailed description of the basic biophysical principles of membrane transport has been avoided to make the discussion more readable. The cited references will, however, help those readers primarily interested in the basic details of sweat gland function. Part I of this article includes a discussion of morphologic characteristics, central and peripheral nervous control of sweat secretion, neurotransmitters, intracellular mediators and stimulus secretion coupling, Na-K-Cl cotransport model for the ionic mechanism of sweat secretion, ingredients of sweat, ductal function, the pathogenesis of abnormal sweat gland function in cystic fibrosis, and the discovery of the apoeccrine sweat gland. Part II, to be published in the May issue of the Journal, reviews reports of all those major disorders of hyperhidrosis and hypohidrosis that have appeared in the literature during the past 10 years. It is hoped that this review will serve as a resource for clinicians who encounter puzzling disorders of sweating in their patients, as well as for investigators who wish to obtain a quick update on sweat gland function.

The current epidemiologic data on hyperhidrosis are scarce and insufficient to provide precise prevalence or impact estimates. We sought to estimate the prevalence of hyperhidrosis in the US population and assess the impact of sweating on those affected by axillary hyperhidrosis. A nationally representative sample of 150,000 households was screened by mailed survey for hyperhidrosis and projected to the US population based on US census data. Ascertainment of hyperhidrosis was based on a question that asked whether participants experienced excessive or abnormal/unusual sweating. The prevalence of hyperhidrosis in the survey sample was 2.9% (6800 individuals). The projected prevalence of hyperhidrosis in the United States is 2.8% (7.8 million individuals), and 50.8% of this population (4.0 million individuals) reported that they have axillary hyperhidrosis (1.4% of the US population). Only 38% had discussed their sweating with a health care professional. Approximately one third of individuals with axillary hyperhidrosis (0.5% of the US population or 1.3 million individuals) reported that their sweating is barely tolerable and frequently interferes, or is intolerable and always interferes, with daily activities. Hyperhidrosis affects a much larger proportion of the US population than previously reported. More than half of these individuals have axillary hyperhidrosis, in which sweating can result in occupational, emotional, psychological, social, and physical impairment.