An acute ulcerative variant of interdigital athletes 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.Plantar athletes foot (moccasin foot) is also caused by T. rubrum which typically causes asymptomatic, slightly erythematous plaques (areas of redness of the skin) to form on the plantar surface (sole) of the foot that are often covered by fine, powdery hyperkeratotic scales.The vesiculobullous type of athletes foot is less common and is usually caused by T. mentagrophytes and is characterized by a sudden outbreak of itchy blisters and vesicles on an erythematous base, usually appearing on the sole of the foot. This subtype of athletes foot is often complicated by secondary bacterial infection by Streptococcus pyogenes or Staphylococcus aureus. Complications
As the disease progresses, the skin may crack, leading to bacterial skin infection and inflammation of the lymphatic vessels. If allowed to grow for too long, athletes foot fungus may spread to infect the toenails, feeding on the keratin in them, a condition called onychomycosis.Because athletes 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 athletes 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.
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
Athletes 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. Dermatophytes are anthropophilic, meaning these parasitic fungi prefer human hosts. Athletes foot is most commonly caused by the molds known as Trichophyton rubrum and T. mentagrophytes, but may also be caused by Epidermophyton floccosum. Most cases of athletes foot in the general population are caused by T. rubrum; however, the majority of athletes foot cases in athletes are caused by T. mentagrophytes. Transmission
According to the UKs National Health Service, "Athletes foot is very contagious and can be spread through direct and indirect contact." 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 athletes foot can easily spread to ones environment. Fungi rub off of fingers and bare feet, but also travel on the dead skin cells that continually fall off the body.