trichophyton

Trichophyton is a genus of filamentous fungi in the family Arthrodermataceae that are common causes of dermatophytosis, or tinea, in humans and animals. Members of this genus are keratinophilic, colonizing keratinized tissues such as skin, hair, and nails. The genus includes species with differing host preferences, including anthropophilic (human-associated), zoophilic (animal-associated), and geophilic (soil-associated) strains. Some species have sexual states that have historically been classified in Arthroderma.

Morphology and ecology are characteristic of dermatophytes: the fungi grow as hyaline, septate hyphae and produce conidia. Macroconidia and microconidia vary among species and are used in identification, alongside colony morphology. Trichophyton species are typically found in warm, humid environments and can persist on contaminated surfaces or objects, contributing to transmission.

Clinically, Trichophyton species are responsible for several common dermatophytoses, including tinea capitis (scalp), tinea corporis (body), tinea cruris (groin), tinea pedis (foot), and tinea unguium (nails). T. rubrum and T. mentagrophytes are among the most frequent causes of human infections, while T. tonsurans is notable for scalp infections in children; T. schoenleinii causes favus, a rarer form of scalp disease. Zoonotic species such as T. verrucosum may be acquired from animals.

Diagnosis relies on clinical assessment supported by laboratory tests. Microscopic examination of skin, hair, or nail scrapings with potassium hydroxide (KOH) preparations and fungal culture on Sabouraud dextrose agar are standard methods; molecular techniques may be used for confirmation. Treatment depends on the site and severity, with topical antifungals (for limited infections) and systemic agents such as terbinafine, itraconazole, or fluconazole for nail or extensive infections. Prevention emphasizes good foot hygiene, avoiding shared personal items, and prompt treatment of lesions.