Hypohidrosis

Hypohidrosis is diminished sweating in response to appropriate stimuli. While hyperhidrosis is a socially troubling but benign condition, hypohidrosis can lead to hyperthermia, heat exhaustion, heat stroke and potentially death.

Medications

 * Anticholinergic agents
 * Opioids
 * Botulinum toxin
 * Alpha-2 receptor antagonists
 * Clonidine
 * Barbiturates

Physical agents

 * Tumours
 * Burns
 * Radiation
 * Surgery
 * Scars

Dermatological

 * X-linked hypohidrotic ectodermal dysplasia
 * Incontinentia pigmenti
 * Bazex disease
 * Fabry disease
 * Miliaria
 * Sjogren syndrome
 * Systemic sclerosis
 * Graft-versus-host disease

Neuropathic

 * Multiple system atrophy
 * Dementia with Lewy bodies
 * Multiple sclerosis
 * Cerebrovascular accident
 * Tumour
 * Encephalitis
 * Cervical myelopathy
 * Diabetes mellitus
 * Guillain–Barre syndrome
 * Hereditary sensory and autonomic neuropathy
 * Alcoholism
 * Amyloidosis
 * Ross syndrome
 * Pure autonomic failure

Diagnosis
Sweat is readily visualized by a topical indicator such as iodinated starch (minor test) or sodium alizarin sulphonate. Both of which undergo a dramatic colour change when moistened by sweat. A thermoregulatory sweat test can evaluate the body’s response to a thermal stimulus by inducing sweating through a hot box ⁄ room, thermal blanket or exercise. Failure of the topical indicator to undergo a colour change during thermoregulatory sweat testing indicates hypohidrosis, and further tests may be required to localize the lesion.

Magnetic resonance imaging of the brain and ⁄ or spinal cord is the best modality for evaluation when the lesion is suspected to be localized to the central nervous system.

Skin biopsies are useful when anhidrosis occurs as part of a dermatological disorder. Biopsy results may reveal the sweat gland destruction, necrosis or fibrosis, in addition to the findings of the primary dermatological disorder.

Management
The treatment options for hypohidrosis and anhidrosis is limited. Those with hypohidrosis should avoid drugs that can aggravate the condition (see medication-causes). They should limit activities that raise the core body temperature and if exercises are to be performed, they should be supervised and be performed in a cool, sheltered and well-ventilated environment. In instances where the cause is known, treatment should be directed at the primary pathology. In autoimmune diseases, such as Sjogren syndrome and systemic sclerosis, treatment of the underlying disease using immunosuppressive drugs may lead to improvement in hypohidrosis. In neurological diseases, the primary pathology is often irreversible. In these instances, prevention of further neurological damage, such as good glycaemic control in diabetes, is the cornerstone of management. In acquired generalized anhidrosis, spontaneous remission may be observed in some cases. Numerous cases have been reported to respond effectively to systemic corticosteroids. Although an optimum dose and regime has not been established, pulse methylprednisolone (up to 1000 mg ⁄ day) has been reported to have good effect.