The medical term for excessive sweating is hyperhidrosis. It affects roughly 5% of the U.S. population, about 15 million people, and ranges from mildly annoying to severe enough to interfere with everyday activities like gripping a steering wheel or shaking someone’s hand.
Hyperhidrosis isn’t just sweating a lot after a workout or on a hot day. It’s sweating that happens beyond what your body needs to cool itself down, often in situations where other people around you stay dry.
Primary vs. Secondary Hyperhidrosis
There are two distinct types, and the difference matters because they have different causes and different implications for your health.
Primary focal hyperhidrosis targets specific areas of the body: the palms, soles of the feet, underarms, and face. The sweating typically happens on both sides of the body (both palms, both underarms) and occurs at least once a week during waking hours. It usually starts during childhood or adolescence. A 2017 survey found that 17.1% of teenagers report excessive, uncontrollable sweating. Primary hyperhidrosis has no underlying medical cause. Your sweat glands are healthy and normal in number. The problem is that the nerves controlling them are overactive, sending “sweat now” signals when your body doesn’t actually need cooling.
Secondary generalized hyperhidrosis is excessive sweating caused by something else: a medication, a hormonal change like menopause or a thyroid disorder, an infection, or another medical condition. This type tends to affect larger areas of the body rather than just the hands or feet, and it can happen during sleep. If you start sweating excessively as an adult without a prior history of it, secondary hyperhidrosis is the more likely explanation.
How It Differs From Normal Sweating
Everyone sweats. Your body has millions of sweat glands, and perspiration is the primary way you regulate temperature. What separates hyperhidrosis from ordinary sweating is the mismatch between what’s happening around you and how much you sweat. You might be sitting in an air-conditioned office, not anxious, not exerting yourself, and your shirt is soaked through. Or your hands drip so much that paper gets damp when you write on it.
People with hyperhidrosis often change clothes multiple times a day, avoid handshakes, or stop wearing certain colors because sweat stains show. The condition carries a significant emotional toll. Many people feel embarrassed or anxious about the sweating itself, which can trigger more sweating in a frustrating cycle.
What Causes It
In primary hyperhidrosis, the part of the nervous system that controls sweating (the sympathetic nervous system) is essentially stuck in overdrive. Your sweat glands themselves are structurally normal. The issue is in the signaling: nerves fire too frequently and too intensely, telling the glands to produce sweat when there’s no real need for it. There’s a strong genetic component. If a parent has it, you’re more likely to develop it.
Secondary hyperhidrosis has a long list of potential triggers. Thyroid problems, diabetes, menopause, certain infections, and some medications (including certain antidepressants and blood pressure drugs) can all cause it. This is why new-onset sweating in adulthood is worth investigating with a doctor. The sweating is a symptom of something else, and treating the underlying cause often resolves it.
When Sweating Signals Something Serious
Most excessive sweating is not dangerous. But certain patterns warrant prompt medical attention. Night sweats that drench your sheets, combined with unexplained weight loss (more than 5% of your body weight over six to twelve months), persistent fatigue, or swollen lymph nodes can be signs of infection or, less commonly, lymphoma or leukemia. Fever alongside drenching night sweats and weight loss is a combination that doctors take seriously and evaluate quickly.
If your excessive sweating started suddenly, only happens at night, or comes with any of those additional symptoms, that’s a different situation from someone who has had sweaty palms since middle school.
Treatment Options
Treatment depends on severity and which body areas are affected. Most people start with the simplest options and escalate if needed.
- Clinical-strength antiperspirants containing 6% to 20% aluminum chloride work by temporarily blocking sweat pores. These are available over the counter in lower concentrations and by prescription in higher ones. They’re effective for mild hyperhidrosis, particularly in the underarms.
- Iontophoresis is a home treatment for hands and feet. You soak them in shallow water while a device passes a mild electrical current through it. The current reduces sweat gland activity over time with regular sessions.
- Botulinum toxin injections block the nerves that trigger sweat glands. This works well for underarms, palms, and other targeted areas, but the effects wear off after about six months, so repeat treatments are needed. A common side effect is temporary muscle weakness near the injection site.
- Prescription medications can reduce sweating more broadly. Some creams target specific areas like the face and head. Certain oral medications used for other conditions, including some antidepressants, also decrease sweating as a side effect, which can be useful for people with both hyperhidrosis and anxiety.
For severe cases that don’t respond to other treatments, surgical options exist that interrupt the nerve signals to sweat glands, though these carry their own risks and are typically a last resort.
Living With Hyperhidrosis
Constant moisture on the skin creates a warm, damp environment where bacteria and fungi thrive. People with hyperhidrosis are more prone to skin infections, athlete’s foot, and body odor, not because they’re less hygienic but because the conditions on their skin are harder to manage. Wearing breathable fabrics, keeping affected areas as dry as possible, and changing socks or undershirts during the day all help.
One of the most important things to know is that hyperhidrosis is a recognized medical condition with real treatments. Many people live with it for years assuming it’s just something they have to deal with. Prevalence data suggests the condition is significantly underdiagnosed. If sweating disrupts your daily life, it’s worth bringing up with a healthcare provider, because effective options exist across a wide range of severity levels.