Dermatophytosis

A number of different species of fungus are involved in dermatophytosis. Dermatophytes of the genera Trichophyton and Microsporum are the most common causative agents. These fungi attack various parts of the body and lead to the conditions listed below. The Latin names are for the conditions (disease patterns), not the agents that cause them. The disease patterns below identify the type of fungus that causes them only in the cases listed: • Dermatophytosis • Tinea pedis (athlete's foot): fungal infection of the feet • Tinea unguium: fungal infection of the fingernails and toenails, and the nail bed • Tinea corporis: fungal infection of the arms, legs, and trunk • Tinea cruris (jock itch): fungal infection of the groin area • Tinea manuum: fungal infection of the hands and palm area • Tinea capitis: fungal infection of the scalp and hair • Tinea faciei (face fungus): fungal infection of the face • Tinea barbae: fungal infestation of facial hair • Other superficial mycoses (not classic ringworm, since not caused by dermatophytes) • Tinea versicolor: caused by Malassezia furfur • Tinea nigra: caused by Hortaea werneckii == Signs and symptoms ==

Infections on the body may give rise to typical enlarging raised red rings of ringworm. Infection on the skin of the feet may cause athlete's foot and in the groin, jock itch. Involvement of the nails is termed onychomycosis. Animals including dogs and cats can also be affected by ringworm, and the disease can be transmitted between animals and humans, making it a zoonotic disease. Specific signs can be: • red, scaly, itchy or raised patches • patches may be redder on outside edges or resemble a ring • patches that begin to ooze or develop a blister • bald patches may develop when the scalp is affected == Causes ==

Fungi thrive in moist, warm areas, such as locker rooms, tanning beds, swimming pools, and skin folds; accordingly, those that cause dermatophytosis may be spread by using exercise machines that have not been disinfected after use, or by sharing towels, clothing, footwear, or hairbrushes. ==Diagnosis==

Dermatophyte infections can be readily diagnosed based on the history, physical examination, and potassium hydroxide (KOH) microscopy. == Prevention ==

Advice often given includes: • Avoid sharing clothing, sports equipment, towels, or sheets. • Wash clothes in hot water with fungicidal soap after suspected exposure to ringworm. • Avoid walking barefoot; instead wear appropriate protective shoes in locker rooms and sandals at the beach. • Avoid touching pets with bald spots, as they are often carriers of the fungus. Vaccination no approved human vaccine exist against dermatophytosis. For horses, dogs and cats there is available an approved inactivated vaccine called Insol Dermatophyton (Boehringer Ingelheim) which provides time-limited protection against several trichophyton and microsporum fungal strains. With cattle, systemic vaccination has achieved effective control of ringworm. Since 1979 a Russian live vaccine (LFT 130) and later on a Czechoslovak live vaccine against bovine ringworm has been used. In Scandinavian countries vaccination programmes against ringworm are used as a preventive measure to improve the hide quality. In Russia, fur-bearing animals (silver fox, foxes, polar foxes) and rabbits have also been treated with vaccines. == Treatment ==

Antifungal treatments include topical agents such as miconazole, terbinafine, clotrimazole, ketoconazole, or tolnaftate applied twice daily until symptoms resolve — usually within one or two weeks. Topical treatments should then be continued for a further 7 days after resolution of visible symptoms to prevent recurrence. The total duration of treatment is therefore generally two weeks, but may be as long as three. In more severe cases or scalp ringworm, systemic treatment with oral medications (such as itraconazole, terbinafine, and ketoconazole) may be given. To prevent spreading the infection, lesions should not be touched, and good hygiene maintained with washing of hands and the body. Misdiagnosis and treatment of ringworm with a topical steroid, a standard treatment of the superficially similar pityriasis rosea, can result in tinea incognito, a condition where ringworm fungus grows without typical features, such as a distinctive raised border. == History ==

Dermatophytosis has been prevalent since before 1906, at which time ringworm was treated with compounds of mercury or sometimes sulfur or iodine. Hairy areas of skin were considered too difficult to treat, so the scalp was treated with X-rays and followed up with antifungal medication. Another treatment from around the same time was application of araroba powder. ==Terminology==

The most common term for the infection, "ringworm", is a misnomer, since the condition is caused by fungi of several different species and not by parasitic worms. == Other animals ==

Ringworm caused by Trichophyton verrucosum is a frequent clinical condition in cattle. Young animals are more frequently affected. The lesions are located on the head, neck, tail, and perineum. The typical lesion is a round, whitish crust. Multiple lesions may coalesce in "map-like" appearance. File:Toplin des dieles tiesse vea.jpg|Multiple lesions, head File:Dieles åtoû d' l' ouy åmea.JPG|Around the eyes and on ears File:2 dieles mashale.jpg|On cheeks: crusted lesion (right) File:Viye diele did près.JPG|Old lesions, with regrowing hair File:Diele vea waerot.jpg|On neck and withers File:Dieles cawî åmea.JPG|On perineum Clinical dermatophytosis is also diagnosed in sheep, dogs, cats, and horses. Causative agents, besides Trichophyton verrucosum, are T. mentagrophytes, T. equinum, Microsporum gypseum, M. canis, and M. nanum. Identifying the species of fungi involved in pet infections can be helpful in controlling the source of infection. M. canis, despite its name, occurs more commonly in domestic cats, and 98% of cat infections are with this organism. It can also infect dogs and humans, however. T. mentagrophytes has a major reservoir in rodents, but can also infect pet rabbits, dogs, and horses. M. gypseum is a soil organism and is often contracted from gardens and other such places. Besides humans, it may infect rodents, dogs, cats, horses, cattle, and swine. Treatment Pet animals Treatment requires both systemic oral treatment with most of the same drugs used in humans—terbinafine, fluconazole, or itraconazole—as well as a topical "dip" therapy. Because of the usually longer hair shafts in pets compared to those of humans, the area of infection and possibly all of the longer hair of the pet must be clipped to decrease the load of fungal spores clinging to the pet's hair shafts. However, close shaving is usually not done because nicking the skin facilitates further skin infection. Twice-weekly bathing of the pet with diluted lime sulfur dip solution is effective in eradicating fungal spores. This must continue for 3 to 8 weeks. Washing of household hard surfaces with 1:10 household sodium hypochlorite bleach solution is effective in killing spores, but it is too irritating to be used directly on hair and skin. Pet hair must be rigorously removed from all household surfaces, and then the vacuum cleaner bag, and perhaps even the vacuum cleaner itself, discarded when this has been done repeatedly. Removal of all hair is important, since spores may survive 12 months or even as long as two years on hair clinging to surfaces. Cattle In bovines, an infestation is difficult to cure, as systemic treatment is uneconomical. Local treatment with iodine compounds is time-consuming, as it needs scraping of crusty lesions. Moreover, it must be carefully conducted using gloves, lest the worker become infested. == Epidemiology ==

Worldwide, superficial fungal infections caused by dermatophytes are estimated to infect around 20-25% of the population and it is thought that dermatophytes infect 10-15% of the population during their lifetime. The highest incidence of superficial mycoses result from dermatophytoses which are most prevalent in tropical regions. Onychomycosis, a common infection caused by dermatophytes, is found with varying prevalence rates in many countries. Tinea pedis + onychomycosis, Tinea corporis, Tinea capitis are the most common dermatophytosis found in humans across the world. Pets are susceptible to dermatophytoses caused by Microsporum canis, Microsporum gypseum, and Trichophyton. A 2013 study looking at 5,175 samples of Tinea in patients in Tehran, Iran found the most prevalent type to be Tinea pedis (43.4%), followed by Tinea unguium. (21.3%), and Tinea cruris (20.7%). == See also ==