Dr Tariq Jagnarine
Family Medicine, Endocrinology/Diabetes

Athlete’s foot is a fungal infection that affects the upper layer of the skin of the foot, especially when it is warm, moist, and irritated. It is also known as tinea pedis and ringworm of the foot. The fungus that causes athlete’s foot is called Trichophyton, and is commonly found on floors and in clothing. Athlete’s foot fungus infects the skin only if conditions are right. It requires a warm and moist environment, such as the inside of a shoe. Because of this, only about 0.75 percent of people who regularly walk about barefooted are affected. However, up to 70 percent of people will, at some point in time, develop athlete’s foot.
Athlete’s foot most commonly develops between the toes. It usually causes burning, stinging, redness, and itching; and can also cause flaking of the skin in some people. It is one of the most common types of fungal infection, but although it is contagious, athlete’s foot usually can be treated with over-the-counter (OTC) medication.

Anyone can get athlete’s foot, but certain behaviours may increase a person’s risk of developing the disease. Factors that increase the risk of getting athlete’s foot include:
* Visiting public facilities barefooted, especially locker rooms, showers, and swimming pools.
* Sharing socks, shoes, or towels with an infected person.
* Wearing tight, closed-toe shoes.
* Keeping feet wet for long periods of time.
* Having sweaty feet.
*Having minor skin or nail injury on the feet

The athlete’s 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. 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, in which 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.

The skin on the foot, especially between the toes, becomes itchy. There is a sensation of stinging or burning. The skin may also become:
* dry, flaky, red scaly, and cracking.
* 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 would spread from toe to toe.
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. People 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 immediately. After touching the affected area, it is important to wash hands thoroughly with soap and warm water.

Athlete’s foot can normally be diagnosed by observing the hallmark signs and symptoms. However, other conditions, such as dermatitis, psoriasis, or a low-grade skin infection, should be ruled out.
The most common test is known as skin lesion potassium hydroxide. In this test, a sample of infected tissue is scraped off and placed in potassium hydroxide (KOH). The KOH solution destroys human cells, leaving only the fungal cells. These can be easily viewed using a microscope.

In the majority of cases, athlete’s foot symptoms are mild, and the patient does not need to see a doctor.
Antifungal medications (creams) which are effective in clearing up the infection can be bought at pharmacies. In severe cases, there may be a need to prescribe more powerful antifungal tablets and creams.
If the skin is very sore and there is a lot of swelling, hydrocortisone could be use initially for short periods.

Although athlete’s foot symptoms are mostly mild, and complications are rare, early treatment significantly reduces the risk of complications. However, severe cases can lead to:

* Fungal nail infection: Untreated athlete’s foot can spread to toenails in a condition known as onychomycosis. The nail becomes thick, opaque, whitish, and crumbly. This may be painful, and inflammation may gather 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 of the hands or feet.

The secret to minimising the risk of developing athlete’s foot is to always have clean and dry feet, shoes, and socks.

* Wash the 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.

* Remove shoes as soon as exercise or sporting activity has ended.

* Wear loose-fitting, well-ventilated shoes, especially during the warmer months. The best materials for shoes are leather or canvas.

* Make sure feet are dry before putting on socks, stockings, or tights. Wear socks made from materials that draw moisture away from the feet, such as cotton, silk, or wool.

* When walking around public swimming pools, communal changing rooms or 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 contract athlete’s foot from their pets.