Athlete's foot, also known as tinea pedi and ringworm of the foot, is a fungal infection that affects the upper layer of the skin of the foot, especially when it is warm, moist and irritated. Athlete's foot is a form of ringworm.
The fungus that causes athlete's foot is called Trichophyton, and is commonly found on floors and in clothing.
Athlete's foot fungus will not infect the skin if conditions are not right - it requires a warm and moist environment. Because of this, only about 0.75% of people who regularly walk about barefoot are affected.
Athlete's foot typically develops between our toes and occasionally on other parts of our feet. It usually causes burning, stinging and/or itching. It is the most common type of fungal infection. Although it is contagious, athlete's foot is usually easily treated with OTC (over-the-counter, no prescription required) medication.
Symptoms of athlete's foot
A symptom is something we feel and describe to other people, while a sign can be seen or detected by others. An example of a symptom is an itch, while a sign could be a rash or skin redness.
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:
Athlete's foot typically develops between our toes and occasionally on other parts of our feet.
The skin may also crack, there may be oozing or crusting blisters, and swelling. The sole and the side of the foot may develop scaling patterns.
In severe cases there may be large, open cracks which reveal raw tissue. This can be painful and exposes the patient to infections.
If left untreated, there is a risk that the infection spreads from one toe to the next, and then the next, a rash may develop on the sides and the bottom of the feet.
Onychomycosis - the toenails may become dry and crumbly.
If the patient scratches the affected area and touches other parts of his/her body, the infection can spread. Doctors say it is important to treat athlete's foot as soon as symptoms appear. After touching the affected area, remember to wash your hands thoroughly with soap and warm water.
Infection can spread to the hands - this is called tinea manuum. Patients who do not wash their hands immediately after touching the affected area in their foot/feet are at higher risk. Tinea manuum is a rare complication of athlete's foot.
Causes of athlete's foot
The athlete foot fungus,Trichophyton, is related to other fungi that cause infections in human skin, hair and nails, examples include jock itch and ringworm. These infections are caused by a group of fungi called dermatophytes. Dermatophytes are parasitic; they feed off other organisms to survive.
These fungi exist harmlessly on human skin. However, as long as the skin is dry and clean, their reproduction is limited. 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 canvass.
If your socks are damp and your 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 contact - this means 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 general humid and warm.
People with weakened immune systems are more susceptible to developing athlete's foot.
Diagnosis of athlete's foot
If a person has athlete's foot, the hallmark signs and symptoms will usually make it pretty evident. Sometimes, a doctor may want to determine whether the patient might have some other condition, such as dermatitis, psoriasis or a low-grade skin infection.
The doctor may scrape some of the skin and check the samples under a microscope (potassium hydroxide test). If fungi are detected, then an antifungal medication will be recommended. If it is not a fungus, the doctor may re-examine the affected area with a Wood's light to determine whether there is a reddish fluorescence caused by a bacterium called erythrasma.
If both the tests come back negative, the skin sample may be sent to the laboratory for further analysis.
On the next page we look at the treatments for athlete's foot, including self care and medications. On the final page we discuss the complications and how to prevent athlete's foot.