Hyperhidrosis (HH) is a condition characterized by increased perspiration beyond what is necessary for normal temperature regulation in the body. Although the exact cause of hyperhidrosis is still under investigation, the mechanism is fairly clear.
The sympathetic nervous system sends signals to the sweat glands, telling them to produce and release sweat.
Sweating is important in controlling the temperature of the body, but in hyperhidrosis, the sweat glands are producing and releasing more than needed for temperature regulation.
We don’t know if it’s an overactive sympathetic nervous system, a defect in the nervous system, or the response of the sweat glands to the nervous system. Regardless, the result is the same.
Sympathetic Nervous System
To better understand the sympathetic nervous system, think of it as the fight or flight nervous system. Although the sympathetic nervous system is always active, it is best known for the fight or flight response.
If you were to see a wild animal and take off in a full sprint, your sympathetic nervous system would jump into action, increasing heart rate, dilating pupils, widening the bronchial passages, and sending blood to your muscles.
This involuntary action prepares your body for action. Stress or fear (also considered part of the fight or flight response), stimulates the sympathetic nervous system and will make you sweat or give you goosebumps.
Research on Sweaty Feet
Approximately 1% to 3% of the US population has hyperhidrosis and many body parts can be affected. The body parts most commonly affected are the palms (palmar HH), the soles (plantar HH), and the armpits (axillary HH). Although it is common for those with excessive foot sweating to also have excess hand sweating, the discussion here will focus on plantar hyperhidrosis.
Certain types of footwear can increase sweating in the feet, but those with hyperhidrosis can experience increases in perspiration due to anxiety or drinks with caffeine or the nicotine in cigarettes and even with spicy food. These food items don’t cause hyperhidrosis, they just exacerbate it. Excessive sweating in the feet can contribute to the development of athlete’s foot, warts, blisters, infections, and foot odor.
The picture to the right shows the appearance of the skin when there is too much moisture. This picture was taken after a 3-hour football game. The white and wrinkled appearance of the forefoot is a common result of both excess pressure and excess moisture. A similar appearance can occur in a condition called pitted keratolysis. Pitted keratolysis is a bacterial infection that commonly occurs in those who have hyperhidrosis.
It is characterized by small pits in the skin under the ball of the foot or the heel. All of the treatments listed below are excellent for preventing and treating pitted keratolysis, but topical antibiotics may also be needed.
When there is excessive moisture around the feet, the skin on the bottom of the feet will appear wet, white, wrinkled, and pitted (as seen above). Individuals who wear enclosed shoes and cotton socks or work in wet environments may experience excessive foot sweating or moisture without having hyperhidrosis. Openings in the skin may form and the feet can become tender or painful.
The excessive moisture in the feet increases the chances for the development of the athlete’s foot. For those with hyperhidrosis, sandals may be difficult to wear without socks because the foot slides within the sandal, making walking and driving dangerous.
Bromhidrosis is the combination of sweaty feet and foot odor. A moist, warm environment is a perfect place for bacterial growth, which is what causes foot odor. Those with hyperhidrosis have a greater chance of having foot odor because the increased moisture increases the chances for bacterial growth.
Treatments for Sweaty Feet
1. Aluminum Chloride
daily or twice daily soaks with aluminum chloride or the application of aluminum chloride solution can be very effective. A concentration of 15% or even higher may be necessary to obtain adequate results. This can cause skin irritation in some individuals.
2. Botulinum Toxin
injections of low-dose botulinum toxin have been shown to be an effective treatment for hyperhidrosis. The effects can last for up to 10 months. Most of the research has focused on the underarms and the palms.
a non-invasive therapy that uses water to conduct a mild electrical current through the skin’s surface. Results are variable but overall have been shown to be effective.
the typical surgical treatment of hyperhidrosis is a sympathectomy. This can be done percutaneously (with a needle and acid application) or with a minimally invasive chest surgery. Select nerves are destroyed by cutting or burning. Side effects do exist including a lack of sweating in certain areas, decreased ability to regulate temperature, decreased alertness, and even increased sweating.
Tips to Control Sweaty Feet and Foot Odor:
- Wear breathable shoes made of canvas or mesh siding. Although leather shoes are generally a good choice, all-leather enclosed shoes will increase perspiration and many leather shoes come with plastic liners, which don’t allow moisture to evaporate.
- Air out your shoes daily. Place them in a well-ventilated area.
- Rotate your shoes. Wear different shoes on different days.
- Pull the insoles out of your shoes at the end of the day to dry out both the insole and the shoe.
- Replace your insoles often. This decreases the odor within the shoe and decreases the chances of fungus infection. Shoe liners may need to be changed weekly or monthly, depending on the amount of perspiration. Luckily they are fairly cheap.
- Go barefoot or wear sandals (if possible) to allow your feet to air out.
- Change your socks at least once during the day.
- Avoid cotton socks and nylon socks. Choose small fiber wool or acrylic blend socks, which will wick away moisture from your feet. More on wicking socks.
- Wash and dry feet thoroughly on a daily basis. Dry between the toes. Good foot hygiene is key in treatment.
Use lamb’s wool if you have wet, white tissue between your toes. Placed between the toes, Lamb’s wool will wick away moisture. It can be found at your local drug store in the foot care section.
- Spray or roll on an antiperspirant before putting on your shoes.
- Use a foot powder on your feet or in your shoes. Choose products with aluminum chloride.
- Soak your feet in black tea water for 30 minutes a day for 7-10 days (2 bags per pint of water – brew tea as usual). Black tea has tannic acid, which is anti-bacterial.
- Soak your feet in cider vinegar and warm water (one part vinegar to two parts warm water) for 45-60 minutes a day.
- Check your feet for fungal nail infection. Peeling and scaling on the bottom of the feet and in between the toes is a classic sign of foot fungus. Increased moisture on the feet can increase the chance of a fungal infection.
Make an appointment with a podiatrist or dermatologist in severe cases. Prescription medications or other treatments may be needed.