anhidrotic

Anhidrotic is an adjective describing a lack of sweating, or an absence or marked reduction of sweat production. In medical contexts it refers to an inability to sweat normally (anhidrosis) or to areas of the body where sweating is reduced (hypohidrosis). Sweating is part of thermoregulation, so anhidrotic conditions can impair the body's ability to regulate temperature, especially in hot environments.

Causes can be congenital or acquired. Congenital anhidrosis often appears as part of ectodermal dysplasias, most notably X-linked hypohidrotic (anhidrotic) ectodermal dysplasia, which stems from mutations in the EDA signaling pathway. In these conditions, the development or function of sweat glands is affected, leading to reduced sweating and heat sensitivity. Acquired anhidrosis can result from autonomic neuropathies, skin diseases that destroy sweat glands, dehydration, or external factors such as medications (anticholinergics, some antidepressants, antipsychotics) or botulinum toxin injections that suppress sweating.

Symptoms range from generalized absence or reduction of sweating to localized areas of the body. Generalized anhidrosis raises the risk of overheating and heat-related illness, while localized forms limit sweating to specific regions. Diagnosis involves clinical history and examination, along with sudomotor tests to assess sweat production. Tests include quantitative sudomotor axon reflex testing (QSART) and pilocarpine iontophoresis, as well as mapping sweating distribution with Minor’s test; genetic testing may confirm congenital syndromes like AED.

Management focuses on preventing overheating, such as environmental cooling, hydration, and careful temperature monitoring. Treating underlying causes or adjusting medications is important; in congenital conditions, multidisciplinary care addresses associated features like dental, hair, or skin findings. The prognosis varies with the cause and extent of sweat gland involvement.