From the site of inoculation, the fungus grows down into the stratum corneum, where it invades keratin. Dermatophytes are unique in that they produce keratinase, which enables them to use keratin as a nutrient source. Infected hairs become brittle, and after three weeks, the clinical presentation of broken hairs is evident. There are three types of infection: Ectothrix: Characterized by the growth of fungal spores (arthroconidia) on the exterior of the hair shaft. Infected hairs usually fluoresce greenish-yellow under a Wood lamp (blacklight). Associated with Microsporum canis, Microsporum gypseum, Trichophyton equinum, and Trichophyton verrucosum. Endothrix: Similar to ectothrix, but characterized by arthroconidia restricted to the hair shaft, and restricted to anthropophilic bacteria. The cuticle of the hair remains intact and clinically this type does not have fluorescence. Associated with Trichophyton tonsurans and Trichophyton violaceum, which are anthropophilic. Favus: Causes crusting on the surface of the skin, combined with hair loss. Associated with Trichophyton schoenleini.
Tinea capitis
Dandruff
Tinea faciei
Seborrhoeic dermatitis
Tinea corporis
Tinea manuum
Tinea cruris
Tinea imbricata