++
AT-A-GLANCE
Primary focal (essential) hyperhidrosis:
Idiopathic and symmetric and can affect the palms, soles, axillae, craniofacial region, groin, other areas, or combination of body sites.
Treatment is based on severity of symptoms and location and follows a stepwise approach.
Secondary hyperhidrosis:
Can occur from underlying systemic illnesses, medications, or both (obtaining a detailed medical history is crucial).
The pattern of sweating is classically generalized, but sometimes can be focal or regional if caused by neurologic disease or trauma, or a primary dermatologic cause (eg, eccrine nevus).
Treatment should target the underlying disease process or eliminate or change medications that the patient takes, but this is often not feasible.
Anhidrosis:
Anhidrosis may occur because of congenital or acquired causes (secondary or idiopathic anhidrosis).
Can become a medical emergency leading to hyperthermia, heat stroke, or death.
++
Eccrine sweating is regulated by neurohormonal mechanisms; a derangement in any part of the regulatory pathways, such as the thermal center, central or peripheral nerve transmission, or eccrine gland sweat secretion can alter sweating. Eccrine sweat glands are innervated by sympathetic nerve fibers; the main neurotransmitter, acetylcholine, binds to the muscarinic receptors on the eccrine sweat glands to produce sweating. Disorders of eccrine sweating can be subdivided into two main categories: excessive sweating (hyperhidrosis) and reduced sweating (hypohidrosis or anhidrosis). Hyperhidrosis is a condition of excessive sweating beyond what is physiologically necessary to maintain normal body temperature. The prevalence at 4.8%, represents around 15.3 million people in the United States.1 Hyperhidrosis can be further subdivided into primary and secondary hyperhidrosis. Pathogenesis of primary or essential hyperhidrosis is poorly understood. Secondary hyperhidrosis can result from underlying systemic illnesses, including, but not limited to, central and peripheral neurologic dysfunctions, endocrine disorders, psychiatric disorders, hormonal imbalance, infections, malignancy, certain primary dermatologic disorders, and from medications or toxins.2 Hyperhidrosis can adversely impact patients’ daily activities, be occupationally restrictive, and interfere with interpersonal relationships.
++
Anhidrosis is characterized by the inability to normally generate sweat when physiologically necessary to dissipate heat. As a result, this can become a medical emergency, leading to hyperthermia, heat stroke, or death. This chapter focuses on reviewing several disorders that can cause focal, regional, and generalized abnormalities in sweating. Please refer to Table 81-1 for an inclusive list of disorders of the eccrine glands and sweating. A review of the normal anatomy and physiology of eccrine sweat glands and sweating may be found in Chap. 6.
++