What causes hypohidrosis?

Causes of Hypohidrosis (Reduced Sweating)

Hypohidrosis is primarily caused by either obstruction of sweat ducts, damage to sweat glands, or neurological dysfunction affecting the autonomic nervous system that controls sweating. 1

Common Causes of Hypohidrosis

Skin-Related Causes

• Obstruction of sweat ducts - Plugging of sweat ducts by hyperkeratosis (excessive skin thickening) is a common cause, particularly in conditions like congenital ichthyosis 2
• Miliaria profunda - Characterized by obstruction of sweat orifices at the stratum corneum level, visible on high-definition optical coherence tomography as sub-stratum corneal hypo-refractile material 3
• Congenital melanocytic nevi - Some patients with these skin lesions have reduced or absent sweat glands in affected areas 2

Neurological Causes

• Central nervous system disorders - Damage to the hypothalamus, brainstem, or spinal cord can disrupt the central control of sweating 4
• Peripheral nerve damage - Conditions affecting peripheral nerves that carry autonomic signals for sweating 1
• Autonomic neuropathy - Often seen in conditions like diabetes or as a medication side effect 5

Genetic/Congenital Causes

• Congenital ichthyosis - A group of genetic skin disorders characterized by dry, scaly skin with associated hypohidrosis 2
• Fabry disease - A rare genetic disorder that can cause decreased sweating as part of its clinical presentation 2
• Ectodermal dysplasias - Congenital disorders affecting tissues of ectodermal origin, including sweat glands 1

Acquired Causes

• Acquired idiopathic generalized anhidrosis (AIGA) - A condition with no detectable abnormalities other than the inability to sweat 1, 3
• Idiopathic partial hypohidrosis (IPH) - Reduced sweating in specific body areas without clear cause 3
• Medication-induced - Anticholinergic drugs can reduce sweating as a side effect 5

Clinical Manifestations

• Heat intolerance - Inability to cool the body through sweating leads to overheating 2
• Hyperthermia - Elevated body temperature due to impaired thermoregulation 1
• Heat exhaustion or heat stroke - In severe cases, especially during physical activity or in hot environments 2
• Compensatory hyperhidrosis - Excessive sweating in areas where sweating is still possible 6

Diagnostic Approach

• Physical examination - Assess for skin abnormalities, neurological signs, and other associated features 1
• Starch-iodine testing - To map areas of reduced or absent sweating 3
• Skin biopsy - May reveal absence or abnormalities of sweat glands in dermatological causes 1
• Neurological evaluation - Including autonomic function tests for suspected neurological causes 1
• Imaging studies - MRI of brain and spinal cord may be indicated for suspected central nervous system lesions 1

Management Options

General Measures

• Avoid extreme temperatures and outdoor activities during hot periods of the day 2
• Wear appropriate clothing to help regulate body temperature 2
• Use cooling devices such as air conditioning and fans 2
• Regular water spraying, bathtubs, or showers to help cool the skin in hot environments 2

Pharmacological Treatment

• Topical therapy may help reduce hyperkeratotic plugging of sweat glands in some cases 2
• Oral retinoids (isotretinoin or acitretin) have shown effectiveness in treating isolated hypohidrosis, with response rates of 90.6% for isotretinoin and 75.0% for acitretin 3
• Systemic corticosteroids may be effective for acquired idiopathic generalized anhidrosis 1

Treatment of Underlying Conditions

• Management of congenital ichthyosis with appropriate skin care and possibly oral retinoids 2
• Treatment of neurological disorders causing hypohidrosis 4
• Discontinuation of medications that may be causing hypohidrosis as a side effect 5

Special Considerations

• Risk of heat injury - Patients with hypohidrosis are at increased risk for heat-related illness and should be educated about prevention 2
• Monitoring during physical activity - Careful monitoring is needed during exercise, especially in hot environments 2
• Emergency action plan - Should be in place for patients at risk of heat-related emergencies 2

Prognosis

• The prognosis depends on the underlying cause
• Isolated hypohidrosis treated with oral retinoids has shown good response with minimal recurrence 3
• Congenital forms may require lifelong management 2
• Acquired forms may improve with treatment of the underlying condition 1