Symptom guide
Excessive sweating: causes, red flags and when to get it checked
Excessive sweating that soaks clothes, occurs without heat or exercise, or disrupts life can be primary hyperhidrosis, a common, harmless overactivity of sweat glands in the hands, feet and armpits, or secondary to another condition. New, generalised sweating, drenching night sweats or sweating with weight loss and fever needs medical review.
Last checked: 2026-10-03
Key facts
At a glance.
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Primary hyperhidrosis
Focal sweating of the palms, soles, armpits or face, often starting in childhood or teens, usually not at night.
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Secondary
Generalised or night sweating that starts in adulthood suggests an underlying cause.
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Common triggers
Anxiety, caffeine, spicy food, alcohol, menopause and certain medicines.
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Red flags
Weight loss, fevers, drenching night sweats, palpitations or a lump need prompt assessment.
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Who to see
GP; dermatology for treatment of hyperhidrosis; endocrinology if hormonal.
What this symptom usually means
Sweating cools the body and is controlled by the sympathetic nervous system. In primary hyperhidrosis the glands are overstimulated without a clear trigger. In secondary sweating, a hormone, infection, medicine or condition drives the system. The pattern, timing and accompanying features distinguish them.
Possible causes, from most to least common
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Primary focal hyperhidrosis: palms, soles, armpits, face or scalp, symmetrical, often familial, typically stops during sleep.
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Anxiety and stress, caffeine, nicotine, alcohol and spicy food.
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Menopause and perimenopause: hot flushes with sweating, night sweats.
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Medicines: antidepressants, opioids, some diabetes drugs, tamoxifen, aromatase inhibitors and many others.
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Overactive thyroid: heat intolerance, weight loss, palpitations, tremor.
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Diabetes and low blood sugar episodes, with shakiness and hunger.
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Infections such as tuberculosis, endocarditis and HIV, with fevers and weight loss.
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Lymphoma and other cancers, phaeochromocytoma, carcinoid, and heart conditions such as a heart attack (cold sweat).
Features that point to something more serious
Drenching night sweats, unexplained weight loss, persistent fevers, new generalised sweating after 40, palpitations, headaches with high blood pressure, a lump, bone pain, itching, sweating with chest pain or breathlessness and sweating that began after a new medicine warrant review.
Red flags: when to seek help
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Call 999: sudden cold sweating with chest pain, breathlessness or collapse.
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Same-day GP: sweating with high fever, rigors or confusion.
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GP within weeks: drenching night sweats, weight loss or persistent fevers.
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Routine: long-standing focal sweating of hands, feet or underarms that interferes with life.
What a doctor will ask and examine
The doctor asks about onset, where you sweat, whether it occurs at night, triggers, medicines, caffeine, alcohol, periods, weight change, fevers, palpitations, heat intolerance and family history. They examine for tremor, thyroid enlargement, lymph nodes, heart and blood pressure and skin.
Tests that are commonly used and why
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Blood tests: full blood count, thyroid function, glucose or HbA1c, inflammatory markers.
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Infection screen and chest X-ray: if fevers or weight loss.
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Menopause assessment is largely clinical; hormone tests are rarely needed over 45.
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Specialist tests (urine catecholamines, imaging) for rare causes.
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Starch-iodine test or sweat measurement: sometimes used to map focal sweating.
Self-care and the usual route
Use clinical-strength antiperspirants (aluminium chloride) at night on dry skin, wear breathable fabrics, avoid known triggers and carry spare clothing. For hands and feet, tap-water iontophoresis is effective. Prescription options include anticholinergic tablets and botulinum toxin injections. Menopausal sweats may respond to hormone therapy or other measures discussed with your doctor.
The NHS route is a GP and dermatology. Private dermatology offers iontophoresis, botulinum toxin and other treatments directly.
Frequently asked
Questions people ask.
Quick, plain-English answers to the questions we hear most.
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What is hyperhidrosis?
A condition of excessive sweating beyond what is needed for temperature control, affecting the hands, feet, armpits or whole body.
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What causes it?
Primary hyperhidrosis has no underlying disease. Secondary causes include menopause, thyroid disease, medicines, infection and other conditions.
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When are night sweats serious?
If they are drenching, persistent and accompanied by fever, weight loss or lumps, they should be evaluated.
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Do antiperspirants help?
Prescription-strength aluminium chloride products are first-line for focal sweating and work well for many people.
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What is iontophoresis?
A treatment passing a mild current through water to reduce sweating of hands and feet, done at home or in clinic.
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Does botox work?
Botulinum toxin injections reduce underarm sweating for several months and are offered by dermatology services.
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Can medicines cause sweating?
Yes. Antidepressants, opioids and diabetes medicines are common culprits, so review of medicines is part of assessment.
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Can anxiety cause it?
Yes. Anxiety increases sweating, particularly of palms and underarms, though primary hyperhidrosis also exists without anxiety.
Where this comes from
Sources and checking.
This guide is for information, not medical advice.
Your GP or consultant knows your history and can tell you which parts apply to you. If your symptoms are severe, rapidly worsening, or come with red-flag features, seek urgent medical care. Figures and availability change, so treat them as a guide and confirm with the provider.
Published 2026-10-03, next review 2027-10-03.
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NHS: Excessive sweating (hyperhidrosis) (nhs.uk/conditions/excessive-sweating-hyperhidrosis/)
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NHS: Overactive thyroid (hyperthyroidism) (nhs.uk/conditions/overactive-thyroid-hyperthyroidism/)
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NICE CKS: Hyperhidrosis (cks.nice.org.uk, topic page)