Athlete’s foot (also known as ringworm of the foot and tinea pedis) is a fungal infection of the skin that causes scaling, flaking, and itch of affected areas.
It is caused by fungi in the genus Trichophyton and is typically transmitted in moist areas where people walk barefoot, such as showers or bathhouses.
Although the condition typically affects the feet, it can spread to other areas of the body, including the groin. Athlete’s foot can be prevented by good hygiene, and is treated by a number of pharmaceutical and other treatments.
Signs and symptoms
Athlete’s foot causes scaling, flaking, and itching of the affected skin. Blisters and cracked skin may also occur, leading to exposed raw tissue, pain, swelling, and inflammation. Secondary bacterial infection can accompany the fungal infection, sometimes requiring a course of oral antibiotics.
The infection can be spread to other areas of the body, such as the groin, and usually is called by a different name once it spreads, such as tinea corporis on the body or limbs and tinea cruris (jock itch or dhobi itch) for an infection of the groin. Tinea pedis most often manifests between the toes, with the space between the fourth and fifth digits most commonly afflicted.
Some individuals may experience an allergic response to the fungus called an “id reaction” in which blisters or vesicles can appear in areas such as the hands, chest and arms. Treatment of the fungus usually results in resolution of the id reaction.
Diagnosis & treatment can be performed by a general practitioner or pharmacist, and by specialists such as a dermatologist, podiatrist & to a lesser extent a foot health practitioner.
Athlete’s foot can usually be diagnosed by visual inspection of the skin, but where the diagnosis is in doubt direct microscopy of a potassium hydroxide preparation (known as a KOH test) may help rule out other possible causes, such as eczema or psoriasis. A KOH preparation is performed on skin scrapings from the affected area.
The KOH preparation has an excellent positive predictive value, but occasionally false negative results may be obtained, especially if treatment with an anti-fungal medication has already begun.
If the above diagnoses are inconclusive or if a treatment regimen has already been started, a biopsy of the affected skin (i.e. a sample of the living skin tissue) can be taken for histological examination. A Wood’s lamp, although useful in diagnosing fungal infections of the hair (Tinea captis), is not usually helpful in diagnosing tinea pedis since the common dermatophytes that cause this disease do not fluoresce under ultraviolet light.
However, it can be useful for determining if the disease is due to a non-fungal afflictor.
The fungi that cause athlete’s foot can live on shower floors, wet towels, and footwear, and can spread from person to person from shared contact with showers, towels, etc.Hygiene, therefore, plays an important role in managing an athlete’s foot infection.Since fungi thrive in moist environments, keeping feet and footwear as dry as possible, and avoiding sharing towels, etc., aids prevention of primary infection.