Fungal Infections of the Feet
By Esther Hansen, D.P.M.
A fungal infection of the feet may infect the soles, in between the toes as well as the toenails. There are many different types of fungi that may infect the feet, but the most common types are dermatophytes. Dermatophytes are fungi that have the ability to utilize keratin, a protein found in skin, hair and nails, as a nutrient source. These organisms colonize in the tissue. This colonization causes an inflammatory response from the host. The host’s response to the fungi varies depending on the particular infecting dermatophyte.
When dermatophytes infect the tissue on the feet, it is called tinea pedis (athlete’s foot). The primary dermatophytes that infect the skin on the feet are Trichophyton Rubrum, Trichophyton Mentagrophytes, and Epidermophyton floccosum. The signs and symptoms associated with tinea pedis include dry, flaky skin on the soles of the feet that is not relieved by moisturizers, itching, burning, peeling and cracking. Tinea pedis in some instances may cause blister formation.
When dermatophytes infect the nail tissue it is called onychomycosis. The two primary dermatophytes that infect the nails are Trichophyton Rubrum and Trichophyton Mentagrophytes. The changes that occur in the nail as a result of a fungal infection include thickening, discoloration, lifting, splitting, and white or yellow streaks.
Fungal infections are spread via direct or indirect contact. Tinea pedis can be spread by walking bare foot in locker rooms, rugs, carpets, showers, pools, to name a few. Trauma such as ingrown toenails, excessive shoe pressures, may offer a portal of entry for a fungal infection to infect the toenails.
There many treatment options for fungal infections of the nails and skin. Tinea pedis is commonly treated with topical antifungal creams and/or gels. When tinea pedis does not completely respond to topical medications, an oral medication may be added to the treatment. Treatment options for onychomycosis include topical medications that are applied daily to the nail, oral antifungal medications and laser therapy.