Hyperhidrosis (Excessive Sweating)

Primary vs secondary hyperhidrosis

Doctors diagnose primary focal hyperhidrosis when visible, excessive sweating has lasted at least 6 months without a clear cause, with at least two of: both sides affected, at least one episode a week, interference with daily life, onset before 25, family history, and no sweating during sleep.

Causes of secondary hyperhidrosis

Hormonal

• menopause and perimenopause (hot flashes and night sweats)
• overactive thyroid
• low blood sugar, especially in diabetes treated with insulin or sulfonylureas
• pregnancy
• rare hormone-producing tumors such as pheochromocytoma or carcinoid

Infections

• tuberculosis, HIV, endocarditis and other chronic infections, typically with night sweats and fever

Cancers

• lymphoma and leukemia, with night sweats, weight loss and swollen glands

Medicines and substances

• antidepressants (especially SSRIs and SNRIs), opioids, insulin, some diabetes drugs, hormone therapy, pilocarpine
• alcohol, caffeine, and withdrawal from alcohol or opioids

Nervous system

• diabetic and other neuropathies
• spinal cord injury and stroke, which can cause one-sided sweating
• Parkinson's disease

Other

• obesity
• anxiety and panic attacks, which cause stress-related sweating but also often coexist with primary hyperhidrosis
• compensatory sweating after surgery for hyperhidrosis

Effects on daily life

Hyperhidrosis can make handshakes, writing, using phones and touchscreens, gripping tools, and wearing certain clothes difficult. Many people experience embarrassment, social anxiety and avoidance. Constant moisture also raises the risk of skin infections, including athlete's foot, warts and bacterial infections, and can cause body odor.

Diagnosis

• history and examination of the sweating pattern
• starch-iodine test: iodine and starch are applied, turning dark purple where sweat is produced, mapping the area for treatment
• gravimetric testing of sweat production in some clinics
• blood tests for secondary causes: thyroid function, blood sugar, blood count, and others guided by symptoms
• Hyperhidrosis Disease Severity Scale: a 4-point scale on how sweating affects daily life, used to plan treatment

Treatment

Treatment is stepped, starting with the simplest options. Secondary hyperhidrosis is treated by addressing the cause.

Topical treatments

• Clinical-strength or prescription antiperspirants with aluminum chloride, applied at night to dry skin. First-line for armpits, hands and feet.
• Topical anticholinergics: glycopyrronium tosylate wipes and sofpironium bromide gel for armpit sweating.

Iontophoresis

The hands or feet sit in shallow water trays while a mild electric current passes through. Sessions of 20 to 30 minutes several times a week, then maintenance, work well for palms and soles. Home devices are available.

Botulinum toxin injections

Botulinum toxin blocks the nerve signal to sweat glands. It is FDA-approved for armpit sweating and also used for hands, feet and face. Results last about 4 to 12 months.

Oral medicines

Anticholinergic tablets such as glycopyrrolate or oxybutynin reduce sweating all over, but can cause dry mouth, blurred vision, constipation and urinary retention. They are used for generalized or multi-site sweating. Beta blockers may help sweating linked to social anxiety.

Procedures

• microwave thermolysis (miraDry) permanently reduces armpit sweat glands
• local sweat gland removal by suction or curettage
• endoscopic thoracic sympathectomy: cutting or clamping nerves in the chest for severe palm sweating. It is effective but often causes compensatory sweating elsewhere, which can be worse, so it is a last resort

Practical tips

• wear loose, breathable fabrics and moisture-wicking socks
• change socks and shoes daily, alternating pairs
• use absorbent underarm pads or dress shields
• keep feet dry and treat athlete's foot

Frequently asked questions

What causes hyperhidrosis?

Primary hyperhidrosis is caused by overactive nerve signals to normal sweat glands, often inherited, with no underlying illness. Secondary hyperhidrosis is caused by conditions such as menopause, overactive thyroid, low blood sugar, infections, some cancers, obesity, or medicines like antidepressants.

What is the best treatment for hyperhidrosis?

Most people start with an aluminum chloride antiperspirant. If that is not enough, options include topical anticholinergic wipes or gel for armpits, iontophoresis for hands and feet, botulinum toxin injections, oral anticholinergic medicines, and microwave therapy for armpits.

Is excessive sweating a sign of something serious?

Usually not, especially if it started in childhood and affects the hands, feet or armpits. New, generalized sweating in adulthood, night sweats with fever or weight loss, or sweating on one side of the body should be checked for an underlying cause.

Can anxiety cause hyperhidrosis?

Anxiety and stress trigger sweating and can make hyperhidrosis worse, but primary hyperhidrosis is not caused by anxiety. It is a physical condition of overactive sweat gland nerves. Living with heavy sweating can, in turn, cause social anxiety.

Does hyperhidrosis go away?

Primary hyperhidrosis often persists for many years, though some people find it improves with age. Treatments control it well for most people. Secondary hyperhidrosis often improves when the underlying cause, such as an overactive thyroid or a medicine, is treated.