Athlete's foot

Athlete's foot is divided into four categories or presentations: chronic interdigital, plantar (chronic scaly; aka "moccasin foot"), acute ulcerative, "Interdigital" means between the toes. "Plantar" here refers to the sole of the foot. The ulcerative condition includes macerated lesions with scaly borders. Athlete's foot occurs most often between the toes (interdigital), with the space between the fourth and fifth digits (the little toe and the fore toe) most commonly affected. Cases of interdigital athlete's foot caused by Trichophyton rubrum may be symptomless, it may itch, or the skin between the toes may appear red or ulcerative (scaly, flaky, or soft and white if skin has been kept wet), with or without itching. An acute ulcerative variant of interdigital athlete's foot caused by T. mentagrophytes is characterized by pain, maceration of the skin, erosions and fissuring of the skin, crusting, and an odor due to secondary bacterial infection. If allowed to grow for too long, athlete's foot fungus may spread to infect the toenails, feeding on the keratin in them, a condition called onychomycosis. Because athlete's foot may itch, it may also elicit the scratch reflex, causing the host to scratch the infected area before they realize it. Scratching can further damage the skin and worsen the condition by allowing the fungus to more easily spread and thrive. 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. Further scratching may remove scabs, inhibiting the healing process. Scratching infected areas may also spread the fungus to the fingers and under the fingernails. If not washed away soon enough, it can infect the fingers and fingernails, growing in the skin and in the nails (not just underneath). After scratching, it can be spread to wherever the person touches, including other parts of the body and to one's environment. Scratching also causes infected skin scales to fall off into one's environment, leading to further possible spread. When athlete's foot fungus or infested skin particles spread to one's environment (such as to clothes, shoes, bathroom, etc.) whether through scratching, falling, or rubbing off, not only can they infect other people, they can also reinfect (or further infect) the host they came from. For example, infected feet infest one's socks and shoes which further expose the feet to the fungus and its spores when worn again. The ease with which the fungus spreads to other areas of the body (on one's fingers) poses another complication. When the fungus is spread to other parts of the body, it can easily be spread back to the feet after the feet have been treated. And because the condition is called something else in each place it takes hold (e.g., tinea corporis (ringworm) or tinea cruris (jock itch)), persons infected may not be aware it is the same disease. 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. Treatment of the underlying infection typically results in the disappearance of the id reaction. == Causes ==

Athlete's foot is a form of dermatophytosis (fungal infection of the skin), caused by dermatophytes, fungi (most of which are mold) which inhabit dead layers of skin and digest keratin. but may also be caused by Epidermophyton floccosum. Most cases of athlete's foot in the general population are caused by T. rubrum; however, the majority of athlete's foot cases in athletes are caused by T. mentagrophytes. The disease may spread to others directly when they touch the infection. People can contract the disease indirectly by coming into contact with contaminated items (clothes, towels, etc.) or surfaces (such as bathroom, shower, or locker room floors). The fungi that cause athlete's foot can easily spread to one's environment. Fungi rub off of fingers and bare feet, but also travel on the dead skin cells that continually fall off the body. Athlete's foot fungi and infested skin particles and flakes may spread to socks, shoes, clothes, to other people, pets (via petting), bed sheets, bathtubs, showers, sinks, counters, towels, rugs, floors, and carpets. When the fungus has spread to pets, it can subsequently spread to the hands and fingers of people who pet them. If a pet frequently gnaws upon itself, it might not be fleas it is reacting to, it may be the insatiable itch of tinea. One way to contract athlete's foot is to get a fungal infection somewhere else on the body first. The fungi causing athlete's foot may spread from other areas of the body to the feet, usually by touching or scratching the affected area, thereby getting the fungus on the fingers, and then touching or scratching the feet. While the fungus remains the same, the name of the condition changes based on where on the body the infection is located. For example, the infection is known as tinea corporis ("ringworm") when the torso or limbs are affected or tinea cruris (jock itch or dhobi itch) when the groin is affected. Clothes (or shoes), body heat, and sweat can keep the skin warm and moist, just the environment the fungus needs to thrive. Risk factors 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. Persons who have had athlete's foot before are more likely to become infected than those who have not. Adults are more likely to catch athlete's foot than children. Men have a higher chance of getting athlete's foot than women. People with diabetes or weakened immune systems == Diagnosis ==

view of cultured athlete's foot fungus When visiting a doctor, the basic diagnosis procedure applies. This includes checking the patient's medical history and medical record for risk factors, Dermatophytes known to cause athlete's foot will demonstrate multiple septate branching hyphae on microscopy. A Wood's lamp (black light), although useful in diagnosing fungal infections of the scalp (tinea capitis), is not usually helpful in diagnosing athlete's foot, since the common dermatophytes that cause this disease do not fluoresce under ultraviolet light. == Prevention ==

There are several preventive foot hygiene measures that can prevent athlete's foot and reduce recurrence. 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. According to the US Centers for Disease Control and Prevention, "Nails should be clipped short and kept clean. Nails can house and spread the infection." Recurrence of athlete's foot can be prevented with the use of antifungal powder on the feet. The fungi (molds) that cause athlete's foot require warmth and moisture to survive and grow. There is an increased risk of infection with exposure to warm, moist environments (e.g., occlusive footwear—shoes or boots that enclose the feet) and in shared humid environments such as communal showers, shared pools, and treatment tubs. Chlorine bleach is a disinfectant and common household cleaner that kills mold. 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 fungi from taking hold and spreading, along with avoidance of sharing footwear and towels during an active fungal infection. == Treatment ==

Athlete's foot resolves without medication in 30 to 40% of cases. Topical antifungal medication consistently produces much higher rates of cure. Conventional treatment typically involves thoroughly washing the feet daily or twice daily, followed by the application of a topical medication. Because the outer skin layers are damaged and susceptible to reinfection, topical treatment generally continues until all layers of the skin are replaced, about 2 to 6 weeks after symptoms disappear. Keeping feet dry and practicing good hygiene (as described in the above section on prevention) is crucial for killing the fungus and preventing reinfection. Treating the feet is not always enough. Once socks or shoes are infested with fungi, wearing them again can reinfect (or further infect) the feet. Socks can be effectively cleaned in the wash by adding bleach or by washing in water . To be effective, treatment includes all infected areas (such as toenails, hands, torso, etc.). Otherwise, the infection may continue to spread, including back to treated areas. For example, leaving fungal infection of the nail untreated may allow it to spread back to the rest of the foot, to become athlete's foot once again. Systematic review found that allylamines such as terbinafine are not more efficacious than azoles for the treatment of athlete's foot. Severe or prolonged fungal skin infections may require treatment with oral antifungal medication. Topical treatments There are many topical antifungal drugs useful in the treatment of athlete's foot including: miconazole nitrate, clotrimazole, tolnaftate (a synthetic thiocarbamate), terbinafine hydrochloride, Potassium permanganate is a salt and a strong oxidizing agent. Oral treatments For severe or refractory cases of athlete's foot oral terbinafine is more effective than griseofulvin. Fluconazole or itraconazole may also be taken orally for severe athlete's foot infections. The most commonly reported adverse effect from these medications is gastrointestinal upset. ==Epidemiology==

Globally, fungal infections affect about 15% of the population and 20% of adults. Additionally, 70% of the population will experience athlete's foot at some point in life. Athlete's foot is common in individuals who wear unventilated (occlusive) footwear, such as rubber boots or vinyl shoes. Upon exposure to an athlete's foot-causing fungus, the moist conditions generated from poor foot ventilation promotes growth of the fungus on the foot or between the toes. Likewise, activities such as marathon running have seen increased prevalence of athlete's foot. Studies have demonstrated that men are infected 2 to 4 times more often than women. 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. In the following year, an epidemiologic study was conducted on incoming freshman to the University of California; it was found that 53% of incoming freshman men had athlete's foot and by year's end that number had risen to 78%. Prevalence of the disease increased in the 1930s, specifically among individuals of higher socioeconomic status; these individuals had more access to common shared spaced such as pools, colleges, and athletic clubs where transmission of athlete's foot-causing fungus was common. 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. Antifungal properties of compounds such as undecylenic acid were studied in the 1940s; products containing zinc undecylenate were shown to be the most effective topical treatment for curing the condition. The use of orally ingested Griseofulvin was shown in the 1960s to be effective in acute cases of athlete's foot. Likewise, recorded incidence of athletes foot decreased among American soldiers in Vietnam who were given Griseofulvins as a preventative drug. 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. As of 2012, research has shown that terbinafine is 2.26 times as likely to cure athlete's foot than treatment with Griseofulvin; comparative studies between itraconazole and terbinafine have shown little difference in effectiveness. == See also ==