Synonyms
Tinea pedis, tinea pedum, foot mycosis, athlete’s foot, dermatophyte infection of the foot spelling: athlete`s foot
Definition
Athlete’s foot is a fungal infection (mycosis) of the foot caused by a specific fungus (dermatophyte) that only affects the skin or skin appendages such as hair or nails. These fungi can break down human keratin (the main component of skin and hair) and thus lead to redness and dandruff.
Frequency
The athlete’s foot (Tinea pedis) is one of the most common skin diseases in Germany, but very few can be treated successfully. According to an epidemiological study, the incidence in Germany among adults is about 20%, in certain population groups such as miners, chemical workers, athletes or swimmers the incidence can be up to 70%. Men are affected somewhat more frequently.
The infection is triggered by a fungus (dermatophyte) on the skin. This fungus is divided into three genera: Trichophyton species, Microsporum species and Epidermophyton species. These pathogens can be transmitted from the soil, from animals or from person to person.
According to current knowledge, there are about 40 different species worldwide. In Central Europe the human-to-human transmitted dermatophyte Trichophyton rubrum is one of the most common pathogens which can be isolated from the skin scales studied. Personal contact is not necessary for transmission, because the spores and hyphae of the fungi can survive and remain contagious for months on objects such as socks, shoes, floors, bath mats or hotel carpets.
The second most common pathogen is the Trichophyton mentagrophytes, also called Trichophyton interdigitale and is usually transmitted by pets. The third most common fungus found is Epidermophyton floccosum. After penetrating the uppermost skin layer (epidermis), these dermatophytes can spread centrifugally, i.e. from the center, and cause inflammation of varying intensity.
Causes
Infection (athlete’s foot) with a dermatophyte can occur wherever a person comes into contact with infectious skin scales that another person has lost naturally by walking barefoot, which can be the case especially in public showers and baths. This is because the fungus can survive for a long time, sometimes for months, not only in dry conditions but also in water. The nature of the infection explains why the disease is so common, especially in professions associated with a daily shower in large communal facilities.
Only a daily scrubbing disinfection of the floors can contain the fungus. Various factors can facilitate infection with the pathogen. The damp-warm climate in a shoe, which is also too tight, plays the most important role.
Since heavy protective shoes are prescribed in some professions, the athlete’s foot is particularly common among chemical workers, for example. Excessive sweating (hyperhidrosis) as well as poor blood circulation in the toes (acrocyanosis) are also favourable factors, because a high number of people with circulatory disorders of the arteries and also the veins suffer from athlete’s foot. Genetic factors that are inherited and anatomical malformations of the foot as well as malpositions, nerve damage of the feet (peripheral neuropathies) and diabetes mellitus are also among the factors that promote athlete’s foot.
Individual factors such as a weakened immune system in HIV/AIDS play only a minor role. However, the pathogens can also penetrate through smaller wounds of the skin and cause an inflammation and subsequently a mycosis. Furthermore, the disease can also be the starting point for further mycoses, e.g. a fungal disease of the nails.
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