Research
Anhidrosis and Hypohidrosis (Inability to Sweat): Research Overview
Anhidrosis is the inability to sweat; hypohidrosis is reduced sweating. While excessive sweating gets more attention, sweating too little can be more dangerous, because sweat is the body's main way of shedding heat. When it affects a large part of the body, the failure to sweat can lead to overheating, heat exhaustion, and potentially life-threatening heatstroke. If you cannot sweat normally and feel unwell, dizzy, or overheated in warm conditions, cool down and seek medical care. This page summarizes the verified research on why sweating can be reduced or absent, who is at risk, and why it matters. It is educational and not a diagnosis.
By the Sweat Explained Editorial Team · Published 2026-07-13 · Last reviewed 2026-07-13 · Educational information, not medical advice.
Key statistics at a glance
inability to sweat
the definition of anhidrosis; hypohidrosis means reduced (not absent) sweating
StatPearls, Anhidrosis
heatstroke
described as the most feared complication of generalized anhidrosis
StatPearls, Anhidrosis
~7 per 10,000
international prevalence of ectodermal dysplasia (per births); the hypohidrotic form is the commonest variant
StatPearls, Ectodermal Dysplasia
often reversible
drug-induced anhidrosis typically resolves after the responsible medication is stopped
StatPearls; Cheshire & Fealey 2008
What anhidrosis and hypohidrosis mean
Sweating is how the human body cools itself: eccrine sweat glands release fluid onto the skin, and its evaporation carries heat away. Anhidrosis is the complete inability to sweat, and hypohidrosis is reduced sweating; the two sit on a spectrum and share the same causes and risks. The problem can be localized (one area or one side of the body) or generalized (widespread).
The distinction matters for risk. Small localized patches of absent sweating are often noticed only incidentally and may cause no trouble at all, because the rest of the body can compensate. Generalized anhidrosis is the dangerous form: if most of the skin cannot sweat, the body loses its main cooling mechanism and core temperature can climb quickly, especially during exercise or hot weather.
Why reduced sweating can be dangerous in the heat
StatPearls emphasizes that anhidrosis is important to recognize because it can be potentially life-threatening due to heat-related illness. When the body cannot sweat, heat builds up, producing heat cramps, heat exhaustion, and (the most feared complication) heatstroke, a medical emergency.
Typical warning signs during heat or exertion include feeling hot and flushed, dizziness, breathlessness, weakness, fatigue, drowsiness, muscle cramps, and difficulty concentrating, while sweating stays absent or scanty. Children are at higher risk because their core temperature can rise faster than an adult's.
What to do: if you know or suspect you don't sweat normally, treat heat seriously: avoid strenuous activity in hot conditions, stay in cool environments, and hydrate. If you or someone else becomes confused, faint, stops sweating despite obvious heat, or has a very high temperature, this is a medical emergency: begin cooling and seek emergency care immediately. Anyone who notices they have stopped sweating normally should have it evaluated by a clinician to find the cause.
What causes reduced or absent sweating
Reduced sweating is a sign, not a single disease. The causes fall into broad categories: problems in the nerves that drive sweat glands, problems in the skin or the glands themselves, medications, and inherited conditions, plus an idiopathic (unexplained) form. The examples below are drawn from the StatPearls review.
| Category | Examples | Notes |
|---|---|---|
| Neurologic / autonomic (nerve pathway) | Diabetic autonomic neuropathy, amyloidosis, Guillain-Barré syndrome, Fabry disease, Ross syndrome, Horner syndrome, multiple system atrophy (Shy-Drager) | Damage anywhere from brain and spinal cord to peripheral nerves can reduce the signal to sweat glands. |
| Skin / gland (dermatologic) | Burns, radiation, systemic sclerosis, Sjögren syndrome; pore obstruction from psoriasis, ichthyosis, miliaria, eczema | Sweat glands are destroyed, scarred, or blocked. |
| Congenital / genetic | Hypohidrotic ectodermal dysplasia, incontinentia pigmenti, Fabry disease | Sweat glands are reduced or absent from birth. |
| Medications | Anticholinergics (atropine, scopolamine), topiramate, zonisamide, clonidine, calcium-channel blockers, some chemotherapy | Usually reversible when the drug is stopped. |
| Idiopathic | Acquired idiopathic generalized anhidrosis (AIGA) | Widespread loss of sweating with no identified cause. |
Illustrative, not exhaustive. Identifying the category guides evaluation and, where possible, treatment.
Medications that can reduce sweating
Drugs are a common and often reversible cause. Medicines with anticholinergic effects, which block the acetylcholine signal that triggers eccrine glands, are the classic example, including atropine and scopolamine, but the effect also appears with certain anticonvulsants (notably topiramate and zonisamide), the blood-pressure drug clonidine, some calcium-channel blockers, and a few chemotherapy agents. Topiramate- and zonisamide-associated reduced sweating with overheating has been reported particularly in children.
The practical point from the reviews is that drug-induced anhidrosis is typically reversible once the responsible medication is stopped or changed, but that is a decision for the prescribing clinician, not something to do on your own. If you suspect a medicine is affecting your ability to sweat and to tolerate heat, raise it with your doctor or pharmacist.
Congenital causes: ectodermal dysplasia
Some people are born unable to sweat normally. The best-known example is hypohidrotic (anhidrotic) ectodermal dysplasia, a genetic condition in which sweat glands, along with teeth and hair, develop abnormally. StatPearls puts the international prevalence of ectodermal dysplasia overall at roughly 7 per 10,000 births, with the hypohidrotic form being the commonest variant. It is most often X-linked, so full expression is usually seen in males, while female carriers show milder, variable features.
Because affected infants may not sweat, they can develop unexplained fevers and dangerous overheating very early in life, sometimes in the first hours or days, which is one reason early recognition matters. Lifelong strategies focus on avoiding overheating: environmental cooling, wetting the skin and clothing, and careful management of heat and exertion.
How it is evaluated and managed
Because reduced sweating is a symptom of many different conditions, evaluation aims to find the cause and gauge how much of the body is affected. Clinicians take a history (including medications and heat tolerance), examine the skin, and may use specialized sweat tests, such as the thermoregulatory sweat test or quantitative sudomotor axon reflex testing (QSART), to map where sweating is preserved or lost and whether the problem is in the nerves or the glands.
Management depends on the cause: stopping a responsible drug, treating an underlying neurologic or systemic disease, and, for everyone affected, practical heat-avoidance measures. Genetic and some neurologic forms are lifelong, so the emphasis is on preventing heat illness rather than restoring sweating. The prognosis is generally most favorable for drug-induced and other reversible causes.
Methodology and limitations
This overview is based on the StatPearls (NCBI Bookshelf) chapters on Anhidrosis and on Ectodermal Dysplasia (peer-reviewed, continuously updated clinical references), supported by a pharmacology review of drug-induced hypohidrosis (Cheshire & Fealey 2008, Drug Safety). Categories, examples, the ectodermal dysplasia prevalence figure, and the heat-illness risk statements were traced to those sources and confirmed.
Limitations: anhidrosis and hypohidrosis have many causes, and reliable population prevalence figures exist mainly for specific conditions (such as ectodermal dysplasia) rather than for reduced sweating in general; the 7-per-10,000 figure is for ectodermal dysplasia overall, not for anhidrosis from all causes. Lists of causes and drugs are illustrative, not exhaustive. This page is general education, not a diagnosis or treatment plan. Reduced sweating can signal a serious condition and raises the risk of dangerous overheating, so it should be evaluated by a qualified clinician.
Frequently asked questions
- What is the difference between anhidrosis and hypohidrosis?
- Anhidrosis is the complete inability to sweat; hypohidrosis is reduced but not absent sweating. They share the same causes and risks and differ mainly in degree (StatPearls).
- Why is not sweating dangerous?
- Sweat evaporation is the body's main cooling mechanism. When it fails over a large area, heat builds up and can cause heat cramps, heat exhaustion, and heatstroke, a life-threatening emergency. Children are at especially high risk.
- What can cause someone to stop sweating?
- Causes include nerve/autonomic damage (e.g. diabetic neuropathy, amyloidosis, Ross syndrome), skin or gland damage (burns, radiation, blocked pores), genetic conditions like hypohidrotic ectodermal dysplasia, and certain medications.
- Which medications can reduce sweating?
- Anticholinergics (atropine, scopolamine) are classic, and the anticonvulsants topiramate and zonisamide, clonidine, some calcium-channel blockers, and certain chemotherapy drugs can too. This is usually reversible once the drug is stopped, a decision for your clinician.
- Can anhidrosis be treated?
- It depends on the cause. Drug-induced and some secondary forms often improve when the underlying cause is addressed. Genetic and some neurologic forms are lifelong, so care focuses on avoiding overheating with cooling measures.
- When should I see a doctor about not sweating?
- If you notice you have stopped sweating normally, or you overheat, feel dizzy, or feel unwell in the heat, have it evaluated. Confusion, fainting, or a very high temperature with no sweating in the heat is a medical emergency: cool down and seek emergency care.
Sources
Primary peer-reviewed studies and official sources first, then reviews and institutional framing (secondary).
- Lu Y, Lu Y, et al. (StatPearls Publishing). Anhidrosis. StatPearls [Internet]. NCBI Bookshelf. Continuously updated. StatPearls
- StatPearls Publishing. Ectodermal Dysplasia. StatPearls [Internet]. NCBI Bookshelf. Continuously updated. StatPearls
- Cheshire WP, Fealey RD. Drug-induced hyperhidrosis and hypohidrosis: incidence, prevention and management. Drug Saf. 2008;31(2):109–126. (secondary) PubMed
How to cite this page
Sweat Explained. Anhidrosis and Hypohidrosis (Inability to Sweat): Research Overview. Published 2026-07-13; last reviewed 2026-07-13. Available at: https://sweatexplained.com/research/anhidrosis-and-hypohidrosis-research
Please cite the original studies for the underlying figures. Journalists are welcome to link to this page; the charts are original renderings of the cited data.