Athlete’s Foot

Overview

Athlete's foot is a skin disease caused by a fungus, usually
occurring between the toes.

The fungus most commonly attacks the feet because shoes create a
warm, dark, and humid environment which encourages fungus growth.

Athlete's foot (tinea pedis) is a common, persistent infection of
the foot caused by a dermatophyte, a microscopic fungus that
lives on dead tissue of the hair, toenails, and outer skin
layers. These fungi thrive in warm, moist environments such as
shoes, stockings, and the floors of public showers, locker rooms,
and swimming pools. Athlete's foot is transmitted through contact
with a cut or abrasion on the plantar surface (bottom) of the
foot. In rare cases, the fungus is transmitted from infected
animals to humans.

Dermatophyte (skin) infections cause raised, circular pimples or
blisters that resemble the lesions caused by ringworm. The
infections are named after the part of the body they infect.
Tinea pedis, therefore, refers to an infection of the feet.

Incidence and Prevalence

Athlete's foot is most common in men from the teenage years to the
early 50s. Prevalence is affected by personal hygiene and daily
activity. People with compromised immune systems are at greater
risk.

Causes

There are at least four dermatophytes that can cause tineas pedis.
The most common is trichophyton rubrum.

Signs and Symptoms

There are four common forms of athlete's foot:

  1. The most common is an annoying, persistent itching of the skin on
    the sole of the foot or between the toes (often the fourth and
    fifth toes). As the infection progresses, the skin grows soft.
    The center of the infection is inflamed and sensitive to the
    touch. Gradually, the edges of the infected area become milky
    white and the skin begins to peel. There may also be a slight
    watery discharge.
  2. In the ulcerative type, the peeling skin becomes worse. Large
    cracks develop in the skin, making the patient susceptible to
    secondary bacterial infections. The infection can be transmitted
    to other parts of the body by scratching, or contamination of
    clothing or bedding.
  3. The third type of tinea infection is often called "moccasin
    foot." In this type, a red rash spreads across the lower portion
    of the foot in the pattern of a moccasin. The skin in this region
    gradually becomes dense, white, and scaly.
  4. The fourth form of tinea pedis is inflammatory or vesicular, in
    which a series of raised bumps or ridges develops under the skin
    on the bottom of the foot, typically in the region of the
    metatarsal heads. Itching is intense and there is less peeling of
    the skin.

People with acute tinea infections may develop similar outbreaks
on their hands, typically on the palms. This trichophyde
reaction, also known as tineas manuum, is an immune system
response to fungal antigens (antibodies that fight the fungal
infection).

Diagnosis

Diagnosis is made by visual observation of the symptoms. The
podiatrist eliminates the possibility of a bacterial infection by
performing a microscopic examination of skin scrapings to
determine the type of fungus causing the infection. Other tests
include growing a fungal culture from skin scrapings and
examining the patient's foot under an ultraviolet light.

Treatment

Tinea infections may disappear spontaneously or persist for
years. They are difficult to eliminate and often recur. Best
results usually are obtained with early treatment before the
fungal infection establishes itself firmly. Antifungal drugs may
be used to fight the infection.

If the infection is bacterial, a course of oral antibiotics may
be prescribed.

If you are experiencing any of the symptoms addressed, we
strongly recommend that you seek the advice of your podiatrist
for proper diagnosis.