![]() Favus is a special type of tinea capitis caused by T. The pustular type of tinea capitis is characterized by discrete or grouped follicular pustules. Abscess type presents itself as a smooth erythematous boggy swelling without follicular pustules. Kerion is characterized by a boggy nodular swelling with follicular pustules and, if left untreated, might give rise to scarring. Occasionally, one may see a mixture of all these types of tinea capitis in the same patient. In the latter type, extension of infection from the less-hairy skin to the scalp occurs, which is seen more in adults. The non-inflammatory types are the grey patch, black dot, seborrhoeic, smooth patch of baldness and the glabrous type (also called the adult type) of tinea capitis. The inflammatory types of tinea capitis include kerion, favus, abscess and pustular (agminate folliculitis) types. Infection also occurs through fomites like towels, combs, hair brushes and theater seats. The infection usually occurs through the use of contaminated blades in the pilgrimage centers where ritual head shaves are carried out in large numbers, mostly in unhygienic and overcrowded surroundings. Male children are more commonly affected. Tinea capitis is the most common infection, which is usually seen in children in the age group of 5-10 years. This condition is called Majocchi's granuloma, clinically evidenced by discrete follicular papulonodules on the legs. Women having tinea pedis due to Trichophyton rubrum are prone to develop a foreign body granuloma that rarely occurs in their legs, where the hair is repeatedly shaven. Ultimately, fibrosis may occur with some of the inflammatory types like favus and kerion if not identified and treated early. The destruction of hair follicular wall and sparse hair structures along with foreign body and Langhan's type of giant cells may also be observed in the dermis in the inflammatory types. Histologically, the non-inf lammatory types show very little or no cell infiltrate in the dermis and the inflammatory types show polymorphous infiltrate due to the cell-mediated immune reaction through their antigens. Therefore, the infectivity is higher with the latter type. The inflammatory type involves only few hairs whereas more hairs are involved in the non-inflammatory type. can mediate an inflammatory reaction, producing boggy nodular swelling called kerion or crusted plaque-like lesions called favus. ![]() induce no inflammation, while the zoophilic species and occasionally few anthropophilic spp. Then, the hyphae start producing spores within the hair cortex (endothrix) or on the surface of the hair cortex (ectothrix), depending on the species involved in the infection. These hyphae cannot pass beyond the keratogenous zone and remain there in the form of a fringe called the Adomson's fringe. In human infection, the spores that get deposited on the stratum corneum invade the hair cortex, elongate, multiply and enter into the hair cortex as intrapilary hyphae. Infection of the hair can occur on any hair-bearing area on the body surface. Trichophyton violaceum has been observed as the most common agent causing tinea capitis in India. The dermatophytes causing trichomycosis are listed in Table 1. Some of the dermatophyte species can also produce perforating organs in the hair shaft. The dermatophytes present in the soil start invading the hair and produce colonies using hair as the substrate, showing their affinity for the hair. The ability of the dermatophytes to grow on the hair can easily be demonstrated by the hair bait technique, which involves placing the sterile (acetone treated and dried) hair in a Petriplate containing soil. The dermatophytes causing trichomycosis may be anthropophilic (human), zoophilic (animal) or geophilic (soil). ![]() Trichomycosis of the animals, although not described here, is also important because of the spread of infection to human and other animals and because the infected hide could be one of the causes for considerable economic loss in leather industries. Finally, hair infection has been suggested to be the portal of entry for deep mycosis due to dermatophytes. There may be infection of the siblings and schoolmates in residential schools, especially with tinea capitis, and endemicity of the infection in Chennai has also been reported. Vellus hair infection in sites other than the scalp may also give rise to recurrent episodes of infection and may maintain chronicity. The antigens of these fungi can induce severe inflammation, which may disable the persons. Human trichomycoses cause great concern due to the cosmetic problem of loss of hair. This field of trichology is gaining importance because of the following facts. Trichomycoses by definition are diseases of the hair caused by fungi.
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