Athlete's foot, known medically as tinea pedis, is a common skin infection of the feet caused by a fungus.

[7] Athlete's foot is caused by a number of different funguses,[3] including species of Trichophyton, Epidermophyton, and Microsporum.

[4] Historically it is believed to have been a rare condition that became more frequent in the 20th century due to the greater use of shoes, health clubs, war, and travel.

This subtype of athlete's foot is often complicated by secondary bacterial infection by Streptococcus pyogenes or Staphylococcus aureus.

[11] If allowed to grow for too long, athlete's foot fungus may spread to infect the toenails,[19] feeding on the keratin in them, a condition called onychomycosis.

The itching sensation associated with athlete's foot can be so severe that it may cause hosts to scratch vigorously enough to inflict excoriations (open wounds), which are susceptible to bacterial infection.

When athlete's foot fungus or infested skin particles spread to one's environment (such as to clothes, shoes, bathroom, etc.)

[citation needed] Some individuals may experience an allergic response to the fungus called an id reaction in which blisters or vesicles can appear in areas such as the hands, chest, and arms.

[13] According to the UK's National Health Service, "Athlete's foot is very contagious and can be spread through direct and indirect contact.

People can contract the disease indirectly by coming into contact with contaminated items (clothes, towels, etc.)

Funguses rub off of fingers and bare feet, but also travel on the dead skin cells that continually fall off the body.

Clothes (or shoes), body heat, and sweat can keep the skin warm and moist, just the environment the fungus needs to thrive.

Besides being exposed to any of the modes of transmission presented above, there are additional risk factors that increase one's chance of contracting athlete's foot.

[11] Athlete's foot can usually be diagnosed by visual inspection of the skin and by identifying less obvious symptoms such as itching of the affected area.

If the diagnosis is uncertain, direct microscopy of a potassium hydroxide preparation of a skin scraping (known as a KOH test) can confirm the diagnosis of athlete's foot and help rule out other possible causes, such as candidiasis, pitted keratolysis, erythrasma, contact dermatitis, eczema, or psoriasis.

[13][24][28] Dermatophytes known to cause athlete's foot will demonstrate multiple septate branching hyphae on microscopy.

Some of these include: keeping the feet dry; clipping toenails short; using a separate nail clipper for infected toenails; using socks made from well-ventilated cotton or synthetic moisture wicking materials (to soak moisture away from the skin to help keep it dry); avoiding tight-fitting footwear; changing socks frequently; and wearing sandals while walking through communal areas such as gym showers and locker rooms.

Cleaning surfaces with a chlorine bleach solution prevents the disease from spreading from subsequent contact.

Cleaning bathtubs, showers, bathroom floors, sinks, and counters with bleach helps prevent the spread of the disease, including reinfection.

Keeping socks and shoes clean (using bleach in the wash) is one way to prevent funguses from taking hold and spreading.

The fungal infection may be treated with topical antifungal agents, which can take the form of a spray, powder, cream, or gel.

[38] Athlete's foot is common in individuals who wear unventilated (occlusive) footwear, such as rubber boots or vinyl shoes.

[38] Countries and regions where going barefoot is more common experience much lower rates of athlete's foot than do populations which habitually wear shoes; as a result, the disease has been called "a penalty of civilization".

[42] By 1928 it was estimated that nearly ten million Americans with cases of athlete's foot; the alarming prevalence of the disease caused for public health concern.

[42] Prevalence in the United States was high enough to call for the use of sterilizing footbaths in the 1932 Olympics in Los Angeles.

It was at this time public health officials adopted the idea that athletes foot was a product of modernity and that dealing with this disease was "a penalty of civilization" as many treatments proved ineffective.

Likewise, recorded incidence of athletes foot decreased among American soldiers in Vietnam who were given Griseofulvins as a preventative drug.

[42] In the 1990s, research supported the use of itraconazole and the Allylamine known as terbinafine as drugs effective at eliminating athlete's foot and also dermatophyte infections on other parts of the body.