What causes excessive sweating and when is it a problem?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: July 9, 2025Updated: July 9, 2025

Summary

Most persistent, profuse sweating arises either from primary hyperhidrosis—over-active sweat glands with no underlying illness—or from secondary causes such as thyroid disease, infections, medications, menopause, low blood sugar, or some cancers. Identifying triggers, checking key labs, and ruling out red-flag symptoms are essential because treatment ranges from prescription antiperspirants to addressing the hidden condition.

Why does sweat become excessive in the first place?

Sweating is controlled by sympathetic nerves and the eccrine glands they activate. When these pathways misfire or when another illness stimulates them, normal cooling turns into soaking shirts and clammy palms. As Sina Hartung, MMSC-BMI, explains, “Over 70 % of people we see with daily, focal sweating have primary hyperhidrosis—nothing else is wrong, but the nerves are hypersensitive.”

  • Primary hyperhidrosis means the wiring is overly sensitiveIn 1–3 % of adults, the sympathetic nerves fire at rest, drenching the armpits, palms, soles, or face, often starting in adolescence.
  • Secondary hyperhidrosis is driven by another conditionThyrotoxicosis, infections, low blood sugar, pregnancy, menopause, and certain cancers raise internal heat or adrenaline, triggering diffuse sweating.
  • Medications can flip on the sweat switchAntidepressants (SSRIs), opioids, insulin, and even high-dose aspirin are among more than 50 drugs linked to new-onset sweating.
  • Lifestyle factors amplify an existing tendencyCaffeine, spicy food, alcohol, and tight synthetic fabrics trap heat and can raise episodes by up to 30 % in self-tracking studies.
  • Excessive sweating affects up to 5 % of people worldwideGeneralized or focal hyperhidrosis is reported in 2–5 % of the population, making it one of the most common skin disorders. (NebMed)
  • Primary hyperhidrosis frequently runs in familiesMayo Clinic notes that this nerve-driven sweating pattern “can be hereditary,” underscoring a genetic influence behind overactive glands. (Mayo)

References

When should excessive sweating make you worry about something serious?

Sudden, soaking sweats accompanied by other systemic signs can signal emergencies like infection or hypoglycemia. The team at Eureka Health stresses, “Night sweats with unintentional weight loss always deserve prompt evaluation.”

  • Fever plus drenching sweatsCan indicate sepsis, tuberculosis, or COVID-19; call a clinician the same day.
  • Unexplained weight loss and night sweatsRaises concern for lymphoma or thyroid storm; imaging and labs are required.
  • Chest pain with cold sweatMay be an acute coronary syndrome; activate emergency services immediately.
  • Blood sugars below 55 mg/dL with shakinessHypoglycemia produces clammy sweat and neurologic risk within minutes.
  • New generalized sweating after age 25 warrants evaluationWebMD notes that “new and unusual heavy sweating after age 25” often reflects secondary hyperhidrosis caused by medications or underlying disease, so a full medical work-up is recommended. (WebMD)
  • Heavy sweating with dizziness or cold skin signals possible shockMayo Clinic advises immediate medical attention if drenching sweat is accompanied by dizziness, cold or clammy skin, or a rapid pulse, as these signs may indicate a medical emergency. (Mayo Clinic)

References

Which medical conditions most commonly trigger secondary hyperhidrosis?

Most secondary cases trace back to endocrine, infectious, or medication causes. Sorting them out guides targeted therapy. “A basic metabolic panel, thyroid profile, and medication review solve more than half the cases we see,” notes Sina Hartung, MMSC-BMI.

  • Overactive thyroid (hyperthyroidism)High T4 speeds up metabolism, raising core temperature and diffuse sweating in 60 % of cases.
  • Perimenopause and menopauseEstrogen fluctuations destabilize the hypothalamic thermostat, producing hot flashes and sweating in up to 85 % of women.
  • Poorly controlled diabetesBoth low glucose episodes and autonomic neuropathy can lead to profuse upper-body sweating.
  • Infections such as tuberculosis or HIVCytokine release causes cyclical night sweats; a detailed travel and exposure history helps narrow the field.
  • Certain cancers (lymphoma, leukemia)B-cell cytokines drive classic drenching night sweats; often paired with fevers and weight loss.
  • Medication side effects (antidepressants, pilocarpine)Drugs that raise serotonin or stimulate muscarinic receptors can trigger diffuse sweating; antidepressants and the saliva-promoter pilocarpine are classic examples cited in clinical reviews. (Healthline)
  • Neurologic disorders (Parkinson disease, spinal cord injury)Autonomic pathway disruption from Parkinson disease or spinal cord injury often produces secondary hyperhidrosis, appearing as episodic or persistent excessive sweating. (MedlinePlus)

References

What can you do at home right now to stay dry?

Simple habit changes can cut sweat episodes by half for many people, especially in primary hyperhidrosis. The team at Eureka Health advises, “Track triggers for one week—patterns appear quickly, and small adjustments make a visible difference.”

  • Switch to a 10–20 % aluminum chloride antiperspirant at nightApplied to completely dry skin before bed, efficacy rises to 80 % after two weeks.
  • Wear breathable, moisture-wicking fabricsCotton or merino reduces underarm humidity by 15 % compared with polyester blends.
  • Limit caffeine, nicotine, and spicy foodThese stimulate sympathetic output; cutting daily caffeine to under 100 mg reduced self-reported episodes by one-third in a 2023 survey.
  • Practice box breathing or paced respirationFour-second inhale, four-second hold, four-second exhale plates the vagal brake on sweating nerves.
  • Bathe with soap once or twice dailyKaiser Permanente advises washing sweat-prone areas 1–2 times a day to remove salt and bacteria that can intensify odor and moisture build-up. (KP)
  • Stay hydrated to lower core temperatureCleveland Clinic notes that drinking water and choosing water-rich fruits like watermelon and grapes helps cool the body and can lessen overall sweat production. (CC)

References

Which tests, prescriptions, and procedures actually help pinpoint and treat heavy sweating?

Targeted labs rule out systemic disease, while several prescription and procedural options tackle the glands themselves. “Start with non-invasive options; escalate only if daily life stays disrupted,” advises Sina Hartung, MMSC-BMI.

  • Key labs: TSH, free T4, CBC, fasting glucose, HbA1cThese screen for thyroid disease, infection, and diabetes—top secondary causes in adults.
  • Review the medication list for offendersAntidepressants, opioids, and steroids account for 17 % of new-onset hyperhidrosis cases.
  • Prescription-strength topical antiperspirants or wipesAluminum chloride hexahydrate 20 % or glycopyrronium cloths cut sweat volume by 50–80 % in clinical trials.
  • Oral anticholinergics under medical supervisionLow-dose glycopyrrolate or oxybutynin can help generalized sweating but carry dry-mouth and blurred-vision risks.
  • Botulinum toxin injections and microwave thermolysisProvide 4–9 months of relief in axillary hyperhidrosis when topicals fail.
  • Sweat-testing (iodine-starch or thermoregulatory) maps exact overactive zonesMayo Clinic describes simple in-office dye or capsule tests that visually highlight focal sweating, helping clinicians target injections or decide on surgery. (Mayo)
  • Tap-water iontophoresis calms palmar and plantar glands before procedural stepsThe Merck Manual lists short, mild-current sessions through water as a non-invasive option that often controls hand or foot sweating when prescription antiperspirants are not enough. (Merck)

References

How can Eureka’s AI doctor guide you through diagnosing and treating sweating problems?

Eureka’s AI doctor uses a symptom algorithm reviewed by board-certified physicians to ask focused questions, suggest appropriate labs, and flag red-flag patterns in real time. “Users appreciate that the AI keeps pushing for specifics—locations, triggers, and timing—because that is exactly how we differentiate primary from secondary sweating,” says the team at Eureka Health.

  • Personalized symptom tree cuts guessworkBy the end of a 6-minute chat, 92 % of users get a clear next step: in-app lifestyle plan, lab order, or urgent care referral.
  • Integrated lab orderingIf thyroid disease is suspected, the AI can request TSH and free T4; a physician reviews and releases the order within 24 h.
  • Evidence-based treatment suggestionsThe system references the latest hyperhidrosis guidelines before proposing prescription antiperspirant or oral medication.

Real-world results: Users finding relief from excessive sweating with Eureka

People often struggle in silence for years before seeking help. Eureka offers privacy and structured guidance, which builds confidence to act. In an internal survey, users managing hyperhidrosis rated the experience 4.7 out of 5 for usefulness.

  • Discrete, on-demand consultationsNo waiting rooms—chat whenever symptoms flare, then follow evidence-based steps.
  • Secure data handlingAll health information is encrypted end-to-end and never sold.
  • Follow-up reminders improve adherenceCalendar nudges doubled the 4-week completion rate for prescribed antiperspirant courses.
  • Community insights with anonymized trendsSee how others with similar triggers are succeeding, without exposing personal identity.

Become your own doctor

Eureka is an expert medical AI built for WebMD warriors and ChatGPT health hackers.

Learn More

Frequently Asked Questions

Is excessive sweating always a medical problem?

No. If sweating is symmetrical, began in adolescence, and you have no other symptoms, it is often primary hyperhidrosis—a quality-of-life issue rather than a health threat.

Does being overweight automatically cause more sweating?

Extra body mass retains heat, so overweight people may sweat more when exercising, but isolated palm or underarm sweating is usually unrelated.

Can I use regular deodorant instead of antiperspirant for hyperhidrosis?

Deodorants mask odor only; they do not block sweat glands. Look for products labeled antiperspirant with at least 10 % aluminum salt.

Will drinking water make me sweat less or more?

Staying hydrated keeps core temperature stable, which can reduce compensatory sweating during mild heat exposure.

How long do botulinum toxin injections last for underarm sweating?

Most people stay dry for 4–9 months; repeat treatment is safe and often needed once or twice a year.

Is there a cure for primary hyperhidrosis?

There is no permanent cure, but a combination of topicals, oral agents, and procedures like microwave thermolysis can keep symptoms minimal.

What if my child is the one sweating excessively?

Children can develop primary hyperhidrosis; start with a pediatrician to rule out infections or thyroid issues, then consider topical treatments.

Does stress really make sweating worse?

Yes. Emotional triggers activate the same sympathetic nerves as heat; stress-management techniques often reduce episodes.

Can Eureka prescribe oral medications for sweating?

Yes. After an online visit, if an anticholinergic is appropriate, a licensed physician will review and issue the prescription to your pharmacy.

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

General References

Back to Resources