Athlete's foot overview

# Overview
- Athlete's foot (tinea pedis) is a fungal infection of the skin that causes scaling, flaking, and itching of affected areas.
- It mainly affects the soles, skin over toes, interdigital spaces and nails. 
- It is typically transmitted in moist areas where people walk barefoot, such as showers or bathhouses.
- Athlete's foot is caused infection with a dermatophyte fungus.
- 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.

# Historical Perspective
- The Oxford English Dictionary documents written usage of the term in 1928 (1928 Lit. Digest 22 December. 16/1), which seems to undercut the claim by W. F. Young, Inc. that the term "athlete's foot" was originated, rather than simply popularized, as part of an advertising campaign for Absorbine Jr. during the 1930s.
- Athlete's foot gained popularity during the World Wars due to a very high percentage of soldiers wearing occlusive footwear and using common baths, etc.

# Pathophysiology
- Athlete's foot is caused by a parasitic fungus and is a communicable disease.
- It is typically transmitted  in moist environments where people walk barefoot, such as showers, bath houses, and locker rooms.
- It can also be transmitted by sharing footwear with an infected person, or less commonly, by sharing towels, socks, footwear or clothes with an infected person.

# Diagnosis

## Physical Examination
- Athlete's foot can usually be diagnosed by visual inspection of the skin. Affected skin appears flaky and macerated and rash is usually diffuse and patchy affecting more than 1 toe and sole of the foot.
- 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.

## Other Diagnostic Studies
- A Wood's lamp, although useful in diagnosing fungal infections of the hair (Tinea capitis), 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.

# Treatment

## Medical Therapy
- There are many conventional medications (over-the-counter and prescription) as well as alternative treatments for fungal skin infections, including athlete's foot.
- Important with any treatment plan is the practice of good hygiene.
- Several placebo controlled studies report that good foot hygiene alone can cure athlete's foot even without medication in 30-40% of the cases.  However, placebo-controlled trials of allylamines and azoles for athletes foot consistently produce much higher percentages of cure than placebo.

## Prevention
- The fungi that cause athlete's foot can live on shower floors, wet towels, and footwear.
- Athlete's foot is caused by a fungus 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, it is very important to keep feet and footwear as dry as possible.