Trichophytosis, spore arrangement of the “endothrix” type. Hair, 20% KOH treatment, original magnification x400.
In this type of infection, hairs do not fluoresce under UV light. Arthroconidia are arranged in parallel rows inside the hair shaft (hence “endo”), and the cuticle is undamaged.
This type of spore arrangement in the hair is characteristic of two species: Trichophyton tonsurans (formerly T. crateriforme) and T. violaceum. Both species are anthropophilic dermatophytes, meaning the only source of infection is humans. However, P. N. Kashkin in “Dermatomycoses” (1954) described a case of an “endothrix” trichophytosis outbreak in an orphanage where a cat served as the source, transferring hair from infected children to healthy ones on its fur.
🙏 Material kindly provided by medical laboratory technician Dmitry Emelyanov.
