Excessive sweating is medically called hyperhidrosis. It’s a condition where your body produces far more sweat than it needs to regulate temperature, sometimes soaking through clothing or dripping off your hands during normal, everyday activities. Prevalence estimates vary widely, but millions of people worldwide deal with it, and it comes in two distinct forms with very different causes.
Two Types of Hyperhidrosis
Hyperhidrosis falls into two categories: primary focal hyperhidrosis and secondary generalized hyperhidrosis. The distinction matters because it determines what’s causing the problem and how it’s treated.
Primary focal hyperhidrosis targets specific areas of the body, most commonly the palms, soles of the feet, underarms, and face. It’s caused by overactive nerve signals that tell your sweat glands to ramp up even when there’s no heat or exercise to justify it. This type typically starts in childhood or adolescence, tends to run in families, and causes at least one episode of excessive sweating per week during waking hours. Importantly, it isn’t caused by another medical condition.
Secondary generalized hyperhidrosis is sweating that happens across larger areas of the body and is triggered by an underlying health issue or a medication side effect. It can start at any age and often includes night sweats, which primary hyperhidrosis usually doesn’t.
What Causes Secondary Hyperhidrosis
A long list of medical conditions can trigger whole-body excessive sweating. Some of the most common include hyperthyroidism (an overactive thyroid), diabetes, menopause, anxiety disorders, heart disease, obesity, Parkinson’s disease, and infections like tuberculosis. Certain cancers, particularly lymphomas, are also known to cause drenching night sweats.
Medications are another frequent culprit. Antidepressants, pain relievers, blood pressure medications, insulin, thyroid hormone replacements, and even common over-the-counter drugs like naproxen can all cause sweating as a side effect. Chronic alcohol use can also disrupt the body’s temperature regulation and lead to hyperhidrosis.
How Severity Is Measured
Doctors often use a simple four-point tool called the Hyperhidrosis Disease Severity Scale. You’re asked one question: “How would you rate the severity of your sweating?” The answers range from “never noticeable and never interferes with daily activities” (a score of 1) to “intolerable and always interferes with daily activities” (a score of 4). A score of 3 or 4 indicates severe hyperhidrosis, the threshold where more aggressive treatment is typically considered.
Treatment Options
Antiperspirants
The first step for most people is a stronger antiperspirant. Regular store-bought formulas contain about 10% active ingredient, while clinical-strength versions go up to 20%. If those don’t work, prescription antiperspirants use aluminum chloride hexahydrate at concentrations of 10% to 15% for underarms and around 30% for hands and feet. These are applied at night to dry skin and work by temporarily plugging sweat gland openings.
Oral Medications
When sweating is widespread or doesn’t respond to topical treatments, oral medications that block the chemical signals triggering sweat production can help. These belong to a class called anticholinergics. They work throughout the body, which means they can cause side effects like dry mouth, blurred vision, and constipation. Treatment typically starts at a low dose and is gradually increased based on how well it works and how tolerable the side effects are.
Botox Injections
Botox injections into the affected skin temporarily block the nerves that activate sweat glands. A study tracking 117 patients over 15 years found that the first round of injections lasted a median of 6 months, and with repeated treatments, the duration of relief increased to a median of 8 months. Some patients experienced relief for over two years from a single session. Botox is most commonly used for underarm sweating but can also be applied to palms and soles.
Iontophoresis
This treatment is designed specifically for sweaty hands and feet. You place your hands or feet in shallow trays of water while a medical device sends a mild electrical current through the surface. The current is thought to temporarily disrupt sweat gland signaling. Sessions typically need to be repeated regularly to maintain the effect, often starting with several treatments per week and tapering to a maintenance schedule.
Red Flags Worth Noting
Most hyperhidrosis is uncomfortable but not dangerous. However, certain patterns deserve prompt attention. Night sweats that regularly wake you up, sweating paired with unexplained weight loss, or excessive sweating alongside a persistent cough or fever can signal something more serious, from infections to lymphoma. Sweating that starts suddenly in adulthood, particularly if it’s generalized rather than limited to your palms or underarms, is more likely to have a secondary cause that needs investigation.