Athlete's foot, known as dermatophytosis of the foot or tinea pedis ("foot fungus"), is a common skin infection that affects the feet. You don't have to be an "athlete" to get it.
In North America, 1 in 10 people have athlete's foot. Men tend to be affected more than women, adults more than children. In about 50% of people with athlete's foot, the condition recurs because the fungus spores survive in skin cracks between the toes.
There are 4 types of athlete's foot: moccasin-type, vesicular or blistered, interdigital, and ulcerative.
Athlete's foot is caused by a fungal infection. The fungi that infect human feet live on the skin, specifically on skin proteins called keratin. These fungi thrive in hot, tropical climates and are recent imports to North America and Europe, brought in by travellers. Wearing tight, non-breathing footwear allows the fungi to flourish and cause athlete's foot. The fungal organisms easily spread from one person to another in moist places where people walk barefoot, such as gym locker rooms and swimming pools. Cuts or blisters on the feet make it easier for these organisms to cause an infection.
Interdigital athlete's foot is the most common type, usually seen between the 4th and 5th toes. Interdigital and moccasin-type athlete's foot are commonly caused by the fungus T. rubrum. Vesicular or blistered athlete's foot is believed to be due to an allergic reaction to fungal organisms, causing blisters to form. Ulcerative tinea pedis occurs in severe cases and can affect large areas, and there's usually a secondary bacterial infection on top of the fungal infection.
Symptoms and Complications
Athlete's foot usually forms between the fourth and fifth (smallest) toes or third and fourth toes, producing skin cracking, white and soggy toes, scaling, and itchiness. The infection can spread to the soles of the feet. It's made worse by sweaty feet and wearing tight socks or shoes that stay in moisture. If a bacterial infection sets in on top of it, the skin will ooze, burn, and smell.
Moccasin-type athlete's foot doesn't cause itching or inflammation. The entire sole and heel become dry and flaky with loose, white scales that appear in a moccasin-like pattern. Sometimes the toenails can also become infected, which makes it more difficult to treat.
People with vesicular or blistered athlete's foot suffer from sore, fluid-filled blisters that occur between the toes and on the arch and sides of the foot. These blisters form in response to an allergic reaction to the fungi causing the athlete's foot.
Interdigital tinea pedis is the most common type and presents as maceration (softened tissue caused by soaking) and scales in the web spaces between the toes. This type may become ulcerative when a secondary bacterial infection occurs. Symptoms include painful ulcers between the toes, which often take a long time to heal.
Tinea pedis can lead to foot or leg infections (cellulitis). This can be particularly worrisome in people who have diabetes or chronic vascular diseases.
Making the Diagnosis
By examining the feet for scaling, itchiness, and strong foot odour, doctors can easily diagnose athlete's foot. Your doctor can confirm the diagnosis and exclude other possible skin conditions such as eczema, ringworm, and psoriasis by taking a scraping of lesions from the feet and sending it to the lab for testing.
Treatment and Prevention
Athlete's foot that's soggy, inflamed, and foul-smelling requires quick medical attention. If the foot is inflamed and your doctor has confirmed that there's a bacterial infection, the infection and inflammation must first be treated before antifungals are used.
Topical antifungals (creams, solutions, gel, and lotions), either over-the-counter or prescription, are usually effective for uncomplicated cases of athlete's foot. When these topical agents don't work, antifungal pills are often prescribed. Some medications used to treat athlete's foot contain both an antifungal and antibacterial ingredient to help speed up healing. In addition, special aluminum acetate wet dressings may be helpful when applied to vesiculated or macerated lesions. Shoes may also be treated with antifungal powders.
A foot condition that doesn't clear up after appropriate treatment may not be due to a fungal or bacterial infection. The symptoms may be caused by some other type of skin disease. That's why it's important to see your doctor to confirm the presence of athlete's foot.
The best way to prevent athlete's foot is with good hygiene. This means keeping the feet cool and dry. After a bath or shower, it's important to thoroughly dry between your toes. Here are some practical tips to keep your feet happy and healthy:
- Keep your feet clean, dry, and cool.
- Whenever possible, take off your shoes to "air out" your feet.
- Clean your feet daily with soap and water.
- Always dry well between your toes.
- Use an absorbent powder such as talcum powder or aluminum chloride powder.
- Wear absorbent socks (e.g., made out of cotton or wool).
- Avoid tight-fitting footwear, since sweaty feet provide ideal conditions for fungal growth.
- Change your socks after exercising or after any excess sweating.