Sure, everyone's feet sweat after running a few miles or sitting in 90-degree weather all day. But if your feet sweat for no apparent reason, you may be suffering from hyperhidrosis of the feet.
Hyperhidrosis is a medical condition that causes an area of the body—or multiple areas—to sweat about four times the amount needed to keep your body temperature regulated, explains the International Hyperhidrosis Society (IHS). When it affects the feet, it's called plantar hyperhidrosis or simply hyperhidrosis of the feet, per IHS.
Wondering whether your foot sweating is over the top? Here's what experts say about this condition and how to treat it.
Who experiences hyperhidrosis of the feet?
The feet are a common site of sweating among people who experience hyperhidrosis.
"Many have multiple areas of sweating; oftentimes hands and feet go together," Dee Anna Glaser, MD, dermatologist at SLUCare Physician Group in St. Louis, tells Health. She says some of her patients have excessive underarm, hand, and feet sweating. And it's not uncommon to sweat profusely in areas such as the groin, buttocks , back, or under the breasts.
Excessive hand and feet sweating often starts very early in life, sometimes as young as 6 months to 1 year, notes Dr. Glaser. "Parents may say their kid 'was always dropping their sippy cup or slipping on the floor, and I always thought they were just clumsy or not coordinated,'" she says.
For people who grow up with hyperhidrosis, the condition can affect their lives personally and professionally. "People who sweat in their hands and feet are often embarrassed to shake people's hands due to sweaty palms or take their shoes off around others. They also might have a hard time with dropping things. I have some patients who are nurses and have a hard time putting in an IV," she says.
Still, many people put off getting treatment.
Adam Friedman, MD, professor of dermatology at George Washington School of Medicine and Health Sciences, says that he often picks up on patients' condition anecdotally during an exam. "I might say, 'I see you're sweating a lot; does that bother you?' and they'll reveal it's something they've dealt with for years," he tells Health. "The patient-reported experience is important with this condition because it impacts their social and personal life in addition to being a physical irritant."
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What causes hyperhidrosis of the feet?
The exact cause of hyperhidrosis isn't known. But scientists do know what happens when someone has this condition. It all begins with nerves in the body that tell your sweat glands to start sweating, says Dr. Friedman.
Whether triggered by hormones, emotions, physical activity, or brain signals that the body is overheating, the sweat glands overreact and produce excess sweat, says the IHS. So, in the instance of sweaty feet, the nerves are sending messages to the sweat glands in the feet to sweat, yet the feet don't need to sweat as often as they are "told" to stay cool.
While hyperhidrosis tends to run in families, experts say more research is needed to determine which genes are associated with the condition. "I might ask a patient if anyone in his family had sweaty feet, and he'll say, 'now that I think about it, my dad did,'" says Dr. Friedman.
When excessive sweating is caused by an underlying health condition, it's called generalized hyperhidrosis. As the Mayo Clinic points out, this type of hyperhidrosis tends to cause all-over sweating, not limited to a specific body part like the feet. But it is possible in rare cases.
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Does hyperhidrosis cause smelly feet?
People often assume that people who sweat a lot must smell. However, Dr. Glaser says this isn't true. "The way I get people to think about it is if you have a stream of water, it usually doesn't smell. It's when it becomes stagnant and not free flowing that you start to get a little bit of an odor," says Dr. Glaser.
"When [sweat] sits on the skin, the bacteria interact with it and that's what creates the odor. Bacteria like dark, moist places, so having a little bit of moisture may make you more likely to have odor, but people who have hyperhidrosis and have big outbreaks of sweating usually don't," explains Dr. Glaser.
However, Dr. Friedman adds that moisture from excessive sweat on the feet can break down the top layer of skin on your feet, which can cause a change of the structure of the skin. "This allows for pathogens to get in," he says.
Pitted keratolysis, a bacterial infection, can eat away at the top layer of skin. It can become smelly and needs to be treated with antibiotics, says Dr. Friedman. Sweaty feet can also set the stage for dermatophytosis complex, a foot fungus that breaks down the skin, allowing more concerning bacteria to enter the body, he says.
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How do you treat hyperhidrosis of the feet?
Because the skin on the soles of the feet is thick, Dr. Friedman says it's hard to get medicine to penetrate. However, there are hyperhidrosis feet remedies, such as the following:
Antiperspirants
When applied to the feet, sweat absorbs the antiperspirant, clogging up sweat ducts in the feet. When the ducts are clogged, they send a signal to stop producing sweat. The antiperspirant usually lasts for a day, says the IHS.
Iontophoresis
The IHS says this procedure involves a device that produces a mild electrical current. A person places their feet in a shallow pan of water through which the current passes from the machine through the skin's surface. Weekly treatments can provide long-term benefits.
Botox (onabotulinumtoxin A)
This FDA-approved treatment is indicated for underarm hyperhidrosis; however, some doctors use it for severe cases of hyperhidrosis of the feet, says the IHS. Botox works by temporarily blocking the release of the chemical that initiates the body's sweat glands.
While it can be effective in the feet, Dr. Friedman warns that it should only be given by a qualified doctor who specializes in hyperhidrosis. "The feet can be a sensitive area and Botox can be painful in the feet, so talk with your doctor about your options," he says.
In addition to the treatments mentioned above, there are things you can do to ease the symptoms of plantar hyperhidrosis. Per the IHS:
- Shoe inserts can help absorb sweat and keep you from slipping.
- Powders can absorb moisture and help with slipping.
- Hanging your shoes on a drier as soon as you take them off can help them dry out, so they are ready to wear again.
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