The fungus that causes athlete's foot is called Trichophyton and is commonly found on floors and in clothing.
Athlete's foot fungus only infects the skin if conditions are right - it requires a warm and moist environment, for example, the inside of a shoe. Because of this, only about 0.75 percent of people who regularly walk about barefoot are affected.
However, up to 70 percent of people will, at some point, develop athlete's foot.
Athlete's foot most commonly develops between the toes. It usually causes burning, stinging, redness, and/or itching; it also causes flaking of the skin in some people.
It is the most common type of fungal infection. Although it is contagious, athlete's foot can usually be treated with OTC medication. However, individuals with a weakened immune system or diabetes should see a doctor as soon as athlete's foot develops.
Fast facts on athlete's foot
Here are some key points about athlete's foot. More detail and supporting information is in the main article.
- Athlete's foot is a fungal infection by a fungus known as Trichophyton
- Generally, OTC medications are adequate to treat athlete's foot
- Sometimes, athlete's foot can spread to the hands; this is called tinea manuum
Causes of athlete's foot
The athlete foot fungus, Trichophyton, is a dermatophyte, related to other fungi that cause infections in human skin, hair, and nails.
These fungi exist harmlessly on human skin; as long as the skin is dry and clean, their reproduction is limited. However, under damp and warm conditions, they multiply rapidly.
Thick, tight shoes are more likely to trigger athlete's foot because they squeeze the toes together, creating ideal conditions for the fungus to thrive. Experts say that plastic shoes, which warm and moisten feet the most, are more likely to bring on athlete's foot than those made from other materials, such as leather or canvas.
If socks are damp and the feet are warm, there is a greater risk of developing athlete's foot.
Athlete's foot can be spread through direct and indirect contact:
- Direct, skin-to-skin contact, as may occur when an uninfected person touches the infected area of somebody with athlete's foot
- Indirect contact - the fungi can infect people via contaminated surfaces, clothing, socks, shoes, bed sheets, and towels
Athlete's foot commonly spreads around swimming pools and communal showers - these places are generally humid and warm.
People with weakened immune systems are more susceptible to developing athlete's foot.
Symptoms and images of athlete's foot
The skin on the foot, especially between the toes, becomes Itchy - there is also a sensation of stinging or burning. The skin may also become:
Sometimes, the skin cracks, and there may be oozing or crusting, itchy blisters, and swelling. The sole and the side of the foot may develop scaling patterns.
Bacterial infections can sometimes occur alongside the condition; when athlete's foot is severe and causes open sores in the skin, it makes it more vulnerable to bacteria.
If left untreated, there is a risk that the infection will spread from toe to toe; a rash may develop on the sides and the bottom of the feet. In rare cases, athlete's foot can spread to the hands, this is known as tinea manuum. The symptoms are very similar to those experienced in the feet. Patients who do not wash their hands immediately after touching the affected area on their foot are at higher risk. Tinea manuum is a rare complication of athlete's foot.
If the patient scratches the affected area and touches other parts of the body, the infection can spread. It is important to treat athlete's foot as soon as symptoms appear. After touching the affected area, it is important to wash hands thoroughly with soap and warm water.
Images of athlete's footWarning!: Some of the following images are graphic.
Athlete's foot - lesion on little toe.
Image credit: Ellington (2009)
An example of athlete's foot on the sole of left foot.
Microscopic view of athlete's foot.
Image credit: Ecorahul (2010)
Close up of athlete's foot on the toes
Severe athlete's foot.
Image credit: Dr. James Heilman (2011)
Severe athlete's foot.
Image credit: Kibbledoode1411 (2011)
Diagnosis of athlete's foot
Athlete's foot can normally be diagnosed by observing the hallmark signs and symptoms. However, a doctor may want to rule out other conditions, such as dermatitis, psoriasis, or a low-grade skin infection.
The most common test is known as skin lesion potassium hydroxide. In this test, the doctor scrapes a sample of infected tissue and places it in potassium hydroxide (KOH). The KOH solution destroys human cells, leaving only the fungal cells; these can be viewed using a microscope.
Treatments for athlete's foot
Creams containing miconazole are commonly recommended for athlete's foot.
In the majority of cases, athlete's foot symptoms are mild, and the patient does not need to see a doctor. OTC medications can be bought at pharmacies which are effective in clearing up the infection.
In severe cases, a doctor may prescribe a more powerful antifungal medication, which is usually taken orally (swallowed).
Home-care for athlete's foot
- Wash feet often with soap and water
- Soak feet in salt water or diluted vinegar to clear up blisters
- Tea tree oil - some evidence shows that soaking feet in a tea tree oil solution can help
- Make sure feet are completely dry after washing, especially between the toes
- Wear clean cotton socks
- To keep feet dry, change shoes and socks often
- Wash towels regularly, do not share them
Medications for athlete's foot
These are known as antifungal medications. They kill the fungus that causes the symptoms. Antifungal medications are available as:
Most topical medications can be bought OTC. Topical means it is applied directly onto the skin. A pharmacist may recommend one of the following antifungal medications:
These oral medications might be prescribed by a doctor, either because symptoms are severe, or if the topical medicines did not work:
Antacids can interfere with the absorption of oral antifungals. Oral antifungals may also affect how some anticoagulant drugs work.
Elderly patients and young children should not be given some types of antifungals. Check with a pharmacist, doctor, or nurse, or read the leaflet that comes with the medication carefully.
Dosages may be different for children. Some of the medications are metabolized by the liver and may require blood work to make sure the patient's liver is healthy before taking.
Some antifungals should not be taken during pregnancy, while others may interfere with the male and female reproductive systems. Individuals who are pregnant, or planning to have children, should check with a doctor.
If the skin is very sore and there is a lot of swelling, the doctor may recommend using hydrocortisone. Low-dose hydrocortisone medications can be bought OTC - higher doses will require a prescription.
How to prevent athlete's foot
The secret to minimizing the risk of developing athlete's foot is to always have clean and dry feet, shoes, and socks.
Experts advise the following:
- Wash feet twice a day with water and soap. Always clean between the toes.
- Keep feet dry. Applying (antifungal) talcum powder to the feet can help. Walk barefoot at home as much as possible.
- Remove shoes as soon as exercise or sports has ended.
- Wear loose-fitting, well-ventilated shoes, especially during the warmer months. The best materials for shoes are leather or canvass.
- Make sure feet are dry before putting on socks, stockings, or tights. Wear socks made from material that draws moisture away from the feet, such as cotton, silk, or wool.
- When walking around public swimming pools and communal changing rooms and shower areas, wear pool slippers.
- Change shoes regularly so that footwear is relatively dry. Shoes need time to dry out.
- Do not share footwear.
- Wash sheets and towels regularly.
- If a pet in the home has hair loss, this could be a sign of athlete's foot - take it to the vet. Humans can catch athlete's foot from their pets.
If a child has athlete's foot, they can still go to school, but the teacher should be told, so that appropriate measures are taken before and during physical education classes. The child should not walk barefoot while at school.
Complications of athlete's foot
Although athlete's foot symptoms are mostly mild, and complications are rare, experts say it is best to treat it promptly. Early treatment significantly reduces the risk of complications.
Fungal nail infection - untreated athlete's foot can spread to toenails (onychomycosis). The nail becomes thick, opaque (whitish), and crumbly. There may be pain and inflammation in the skin under the nail. Untreated toenail infections may eventually lead to more pain and problems wearing shoes, or even walking.
Secondary bacterial infection - if this develops the foot may become painful, hot, and swollen.
Infected lymph system - the infection can sometimes spread to the lymph system. Lymphangitis is an infection of the lymph vessels, and lymphadenitis is an infection of the lymph nodes.
Cellulitis - this is a bacterial infection deep in the skin. Skin, fat, and soft tissue may be affected. Untreated cellulitis can lead to serious complications, such as septicemia (blood poisoning) or bone infection. Although a very rare complication of athlete's foot, cellulitis should be treated immediately with antibiotics.
Allergy - some people are allergic to the fungus that causes athlete's foot, this can cause blistering on the hands or feet.