Athlete's Foot

Athlete's foot is a superficial skin infection of the foot caused by a moldlike fungus.

Athlete's foot was relatively uncommon in humans before we began wearing shoes. It is now found frequently in adolescents and adults.

A fungus known as a dermatophyte causes athlete's foot.

• This fungus can be contracted by sharing the shoes of an infected person.

• It needs a warm moist environment to flourish and has been found growing on the floors of locker rooms and public showers and in swimming pools and whirlpools.

• The fungus can also be transmitted by contact with pets who carry it on their fur.

• Most commonly, athlete's foot is characterized by cracking and itchy, moist, white, scaly lesions or sores between the toes. It frequently spreads to the sole of the foot.

• Another type of athlete's foot is a dry, scaly form that causes a reddish "moccasin-like" area over the soles of the feet. This type often affects both feet.

• Less frequently, this infection may involve painful blistery lesions, which can be weepy and may have a strong odor.

A simple fungal infection such as athlete's foot can become "super-infected" with bacteria. If this should happen, the rash will become increasingly painful and red. Your foot may become swollen, and you may develop blisters and even open sores in the infected area. These are indications that you may need oral antibiotics and will need to call your doctor.

It is unlikely that athlete's foot would ever become severe enough that a trip to a hospital's emergency department is required. However, if you have diabetes or any other type of illness that will make it hard for your body to fight off an infection, athlete's foot may become an emergency.

If you develop severe pain, redness, or swelling, notice a puslike drainage, see large blisters or ulcers on your foot, or if you develop a fever, you should be seen as soon as possible by your doctor, who may direct you to an emergency department.

The diagnosis of athlete's foot can usually be made simply by looking at the rash. The diagnosis can also be confirmed by looking at a scraping of the infected area of the foot under a microscope. The doctor will see microscopic yeast cells on the slide.

If the doctor suspects a secondary infection by bacteria, the doctor may look at your foot with a special blue light called a Wood's lamp. If your foot is infected with specific bacteria called Pseudomonas aeruginosa, the rash will fluoresce a greenish color. This test will aid your doctor in choosing the proper antibiotic.

|Self-Care at Home|

• Many over-the-counter antifungal medications can be applied to the affected area. These creams should be used sparingly but regularly, at least once a day. An application the size of a chocolate chip should be adequate to cover the entire bottom of your foot.

• It is important to keep your feet clean and dry. Wear clean absorbent socks made of natural fibers, such as cotton, and change them during the day if your feet become moist or sweaty.

• If possible, remove the insoles of shoes and sneakers to allow them to dry out over night.

• Dusting the inside of your shoes and socks with talcum powder or a medicated powder such as Desenex will help to decrease the moisture level.

• Alternate wearing different pairs of shoes to allow them to dry out for a day or two at a time.

|Medications|

Over-the-counter antifungal creams are sufficient for treating most cases of athlete's foot. Apply them as directed to the toes and foot. Common brands include clotrimazole (Lotrimin) and tolnaftate (Tinactin).

If the topical antifungal medications do not clear up the infection, your doctor may prescribe an oral antifungal medication.

|Prevention|

Simple precautions may help.

• Wear sandals in public locker rooms and swimming areas.

• Do not wear someone else's shoes, especially if that person has athlete's foot.

• Thoroughly clean home showers and floors where family members walk barefooted to avoid spreading the fungus.

|Outlook|

Most cases of athlete's foot go away within 2 weeks. More severe cases may take a month or even longer.

tinea pedis, foot fungus, athlete's foot, fungal infection, skin infection

Author: D Troy Levitt, MD, Director, Department of Emergency Medicine, Chinle Hospital.

Coauthor(s): James Levitt, DPM, Chair, Department of Podiatry, Chinle Comprehensive Healthcare Facility.

Editors: Scott H Plantz, MD, FAAEM, Research Director, Assistant Professor, Department of Emergency Medicine, Mount Sinai School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, ; Anthony Anker, MD, FAAEM, Attending Physician, Emergency Department, Mary Washington Hospital, Fredericksburg, VA.