Athlete's foot is the common name for a fungal infection of the foot, often called ringworm (although there is no worm involved). The three fungi most commonly implicated in athlete's foot— Trichophyton rubrum, T. mentagrophytes, and Epidermophyton floccosum —favor the warm, moist areas between the toes and tend to flare up during warm weather. Similar infections can occur in the nails, scalp, groin, and beard.

Infection with these fungi generally causes mild scaling between the toes, but it can also cause more severe scaling, an itchy red rash, or blisters that cover the toes and the sides of the feet. Since the fungus may also cause the skin to crack, it can lead to bacterial infections, especially in older people or those with poor circulation in their feet. If the infection takes root under the toenails, it is called onychomycosis, and can be very difficult, if not impossible, to eradicate.

Because the fungi that cause athlete's foot thrive in warm, moist areas, it's important to keep the feet clean and dry. Over-the-counter or prescription topical antifungal treatments containing miconazole, clotrimazole, econazole, or ketoconazole can generally cure athlete's foot, but treatment may have to be continued for a month or more for full results. In severe cases, oral antifungal medications may be necessary.

Preliminary evidence suggests that tea tree oil might be helpful for athlete's foot.

Tea Tree Oil

Tea tree oil ( Melaleuca alternifolia) has a long traditional use in Australia for the treatment of skin and other infections. This use is supported by evidence that tea tree oil is an effective antiseptic, active against many bacteria and fungi.1,2 Three double-blind studies suggest it may be helpful for athlete's foot.

In a double-blind, placebo-controlledtrial, 158 people with athlete’s foot were treated with placebo, 25% tea tree oil solution, or 50% tea tree oil solution, applied twice daily for 4 weeks.20 The results showed that the two tea tree oil solutions were more effective than placebo at eradicating infection. In the 50% tea tree oil group, 64% were cured; in the 25% tea tree oil group, 55% were cured; in the placebo group 31% were cured. These differences were statistically significant. A few people developed dermatitis in response to the tea tree oil and had to drop out of the study, but most people did not experience any significant side effects.

Another double-blind, placebo-controlled trial followed 104 people given either a 10% tea tree oil cream, the standard drug tolnaftate, or placebo.3 The results showed that tea tree oil reduced the symptoms of athlete's foot more effectively than placebo, but less effectively than tolnaftate.

A third double-blind study followed 112 people with fungal infections of the toenails, comparing 100% tea tree oil to a standard topical antifungal treatment, clotrimazole.4 The results showed equivalent benefits; however, because topical clotrimazole is not regarded as a particularly effective treatment for this condition, the results mean little.

For more information, including dosage and safety issues, see the full Tea Tree article.