Trichophyton tonsurans is a dermatophyte. The fungus mainly attacks skin and its appendages, i.e. hair and nails. It belongs thereby to one of the most important pathogens of the Dermatophytosen or also the Tinea.
What is Trichophyton tonsurans?
Trichophyton tonsurans is a filamentous or hyphal fungus. It also includes other dermatophytes such as Epidermophyton floccosum or Microsporum. They are called dermatophytes because they primarily infect the skin, hair and nails. Trichophyton tonsurans is a parasite. Parasitism is a form of coexistence between two organisms in which one benefits at the expense of the other. Tinea is the name given to some diseases caused by Trichophyton tonsurans as well as other dermatophytes. This is usually a reddening of the skin characterized by increased scaling and vesicle formation. Tinea can develop almost anywhere and spread from there to other areas of the skin. In this case, however, the fungus spreads only on the superficial layers of the skin. Trichophyton tonsurans can not only transmit from person to person, but it can also be on animals and thus infect humans on contact.
Occurrence, distribution and characteristics
Trichophyton tonsurans is distributed worldwide. It should be noted that circa 10 to 20 percent of the world’s population suffers from fungal infection. Typical habitats of Trichophyton tonsurans are moist and warm places, which in humans are mainly between skin folds and the interstices of toes and fingers. In addition, nails but especially hair are places where Trichophyton tonsurans spreads. Infectious skin flakes are constantly shed, which can also infect other people on contact. Transmission of Trichophyton tonsurans is primarily anthropophilic, meaning from person to person. This can occur directly, for example when many people are together, as is especially the case in changing rooms and communal showers, or indirectly. Since Trichophyton tonsurans mainly infects hair, infectious hair and dandruff can contaminate combs or hats, which can be passed on to other people when they wear them. Rather less is animal-to-human transmission, also called zoophilic transmission. In addition, the pathogen can reside in soil, so it is transmitted to humans during gardening, for example. Trichophyton tonsurans is a filamentous or hyphal fungus. These need energy for their growth, which they obtain from the keratin of the skin. For this they have as virulence factor the keratinase, which releases the keratin from the skin or the nails. Furthermore, Trichophyton tonsurans possesses proteinases, as well as elastases. In order to diagnose the fungus, a small amount of sample material is required, which can be obtained by scraping the affected skin area. This can either be microscoped or cultured. During microscopy, the so-called conidia can be observed. This is the asexual spore, which can occur as a secondary form in the fungus. It is mainly microconidia that are observed in Trichophyton tonsurans, macroconidia are rarely seen. The spores of the fungus are stable permanent forms that can still be infectious for months. If a culture of the fungus is set up, a white-yellowish or reddish-brown flat colony characterized by a velvety or granular appearance can be observed after a few weeks. In the case of Trichophyton tonsurans, only the anamorphic form has become known so far, i.e. the asexual form. The telemorphic form, that is, the sexual form, has not yet been discovered.
Diseases and ailments
Trichophyton tonsurans is a typical causative agent of dermatomycosis. This is a fungal disease that occurs in the skin and skin appendages. Another name is tinea. This varies in appearance, but it usually appears as a reddish scaling of the skin. Thus, tinea corporis is characterized by the fact that an area of skin begins to shimmer and scale reddish and this increasingly spreads outward. The shed scales are highly infectious. Further, the fungus can also spread in the nail and cause nail mycosis (tinea unguium). In this case, the nail becomes very brittle and turns brownish-yellow.However, Trichophyton tonsurans is the most frequent pathogen of hair mycosis, which can affect the head hair or the beard hair (Tinea capitis or barbae). The fungus grows in the hair in the direction of the hair follicle, there it encloses the hair, in order to penetrate afterwards into the hair, which is called also endothrich. After it forms spores and hyphae there, the hair becomes more brittle and has a strong tendency to break. In the most severe cases, this results in kerion, a growth on the head.
