Anhidrosis (Absence of Sweating)

What is Anhydrosis?

Anhidrosis, also spelled anhidrosis, is the medical term for a reduced ability or complete loss of sweating. Sweating is a vital thermoregulatory mechanism; when the body cannot produce sweat, it struggles to cool down, which can lead to overheating, heat‑related illness, and skin problems. Anhidrosis may affect the entire body (generalized) or be limited to specific areas such as the hands, feet, or face (localized).

The condition can be congenital (present at birth) or acquired later in life. Its severity ranges from a mild decrease in sweat output to a complete inability to sweat, and it may be temporary or chronic depending on the underlying cause.

Key point: While occasional reduced sweating can be normal (e.g., in cool environments), persistent or widespread anhidrosis warrants medical evaluation.

Common Causes

Many different disorders, injuries, or medications can impair the sweat glands or the nerves that control them. The most common causes include:

• Peripheral neuropathy – damage to the nerves that stimulate sweat glands (e.g., diabetic neuropathy, leprosy).
• Autonomic nervous system disorders – conditions such as multiple system atrophy or Parkinson’s disease.
• Skin disorders – extensive psoriasis, ichthyosis, or severe burns that destroy sweat glands.
• Medications – anticholinergics (e.g., atropine), antihistamines, certain antipsychotics, and some chemotherapy agents.
• Genetic syndromes – e.g., hereditary sensory and autonomic neuropathy (HSAN) type III (Riley‑Day syndrome) or ectodermal dysplasia.
• Infections – Lyme disease, HIV, or fungal infections that affect nerve function.
• Systemic illnesses – Sjögren’s syndrome, sarcoidosis, and amyloidosis can infiltrate glands.
• Trauma or surgery – injury to the spinal cord, brachial plexus, or removal of sweat glands during skin surgery.
• Heat‑related illnesses – severe heat stroke can temporarily shut down sweat production.
• Idiopathic – in some cases no identifiable cause is found; this is termed idiopathic anhidrosis.

Associated Symptoms

Because sweating is linked to heat regulation, other signs often appear alongside anhidrosis:

• Intense heat intolerance or feeling “overheated” in mild temperatures.
• Flushed or reddened skin, especially on the face, neck, and chest.
• Dry skin that may become cracked or scaly.
• Unusual fatigue or weakness during physical activity.
• Rapid heart rate (tachycardia) as the body tries to compensate for heat.
• Headache, dizziness, or light‑headedness.
• Muscle cramps or cramps in the extremities.
• In severe cases, signs of heat‑related illness: nausea, vomiting, confusion, or loss of consciousness.

When to See a Doctor

Prompt evaluation is recommended if you notice any of the following:

• Sudden loss of sweating in a localized area (e.g., after a burn or infection).
• Persistent inability to sweat over weeks or months.
• Accompanying neurological symptoms such as tingling, numbness, or weakness.
• Frequent episodes of overheating, fainting, or heat exhaustion.
• Dry skin that becomes painful, cracks, or develops infections.
• Any new medication that coincides with the onset of anhidrosis.

These signs may indicate an underlying disease that requires treatment beyond simple symptom management.

Diagnosis

Diagnosing anhidrosis involves a combination of history‑taking, physical examination, and specialized tests.

1. Medical History and Physical Exam

• Review of symptom onset, progression, and possible triggers (medications, trauma, infections).
• Full skin exam to look for scarring, lesions, or areas of absent sweat pores.
• Neurological assessment to detect sensory or motor deficits.

2. Sweat Tests

• Quantitative Sudomotor Axon Reflex Test (QSART): Measures sweat output after a mild electrical stimulus.
• Thermoregulatory Sweat Test (TST): Patient is coated with a powder that changes color with moisture; the pattern of sweating is visualized under controlled temperature.
• Minor’s Starch‑Iodine Test: Simple office test where iodine and starch are applied to the skin; a color change indicates active sweat glands.

3. Laboratory Studies

• Blood glucose and HbA1c (diabetes screening).
• Autoimmune panels (ANA, anti‑SSA/SSB for Sjögren’s).
• Serology for infections (Lyme, HIV).
• Genetic testing when a hereditary syndrome is suspected.

4. Imaging

• MRI or CT of the spinal cord and brain if a central nervous system lesion is suspected.
• Skin biopsy in rare cases to assess sweat gland density.

Treatment Options

Treatment focuses on addressing the underlying cause, protecting the skin, and preventing overheating.

1. Treat Underlying Disease

• Diabetes – strict glycemic control, medications, lifestyle changes.
• Autoimmune conditions – immunosuppressive or immunomodulatory drugs (e.g., hydroxychloroquine for Sjögren’s).
• Medication review – stopping or substituting anticholinergic drugs under physician guidance.
• Infections – appropriate antimicrobial therapy.

2. Symptomatic Management

• Cooling strategies: portable fans, cooling vests, damp cloths, and air‑conditioned environments.
• Hydration: drink water or electrolyte solutions regularly, especially in warm weather or during exercise.
• Skin care: use fragrance‑free moisturizers to keep skin from cracking; apply barrier ointments if skin becomes raw.
• Physical activity modification: exercise during cooler parts of the day, limit intensity, and schedule rest periods.

3. Pharmacologic Options

• Topical anticholinergic agents (e.g., glycopyrrolate cream) are sometimes used to manage hyperhidrosis but are not useful for anhidrosis; however, they may be considered if a mixed pattern of sweating exists.
• Systemic cholinergic agonists (e.g., pilocarpine) have limited efficacy and can cause side effects; they are rarely prescribed.

4. Emerging Therapies

• Botulinum toxin injections can reduce excessive sweating in focal areas, but they do not treat anhidrosis.
• Research into gene therapy for hereditary forms is ongoing but not yet clinically available.

Prevention Tips

While not all cases of anhidrosis are preventable, many risk factors can be minimized:

• Maintain optimal control of chronic diseases such as diabetes and hypertension.
• Limit exposure to medications known to inhibit sweat production; discuss alternatives with your prescriber.
• Protect skin integrity – avoid harsh chemicals, use gentle cleansers, and moisturize daily.
• Practice safe sun exposure; excessive UV damage can scar sweat glands.
• Wear protective footwear and gloves when working with chemicals or in extremely hot environments to reduce skin injury.
• Stay hydrated and avoid prolonged exposure to high temperatures, especially if you have a known risk factor for reduced sweating.

Emergency Warning Signs

Bottom Line

Anhidrosis is more than just “not sweating”; it is a sign that the body’s natural cooling system is compromised. Early recognition, identification of the cause, and implementation of cooling and skin‑protective measures can prevent complications such as heat stroke, skin breakdown, and reduced quality of life. If you notice persistent dryness, overheating, or any of the warning signs listed above, consult a healthcare professional promptly.

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References:

• Mayo Clinic. “Anhidrosis.” mayoclinic.org. Accessed April 2026.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “Diabetic Neuropathy.” niddk.nih.gov.
• Centers for Disease Control and Prevention. “Heat-Related Illness.” cdc.gov.
• Cleveland Clinic. “Sweating Disorders.” clevelandclinic.org.
• World Health Organization. “Guidelines on Heatwaves and Health.” who.int.
• J. Lanigan et al., “Quantitative Sudomotor Axon Reflex Testing in Diagnosis of Autonomic Disorders,” *Neurology*, 2021.