Hair Perforation Test for Dermatophytes
To distinguish between isolates of dermatophytes, particularly Trichophyton mentagrophytes and its variants.
Autoclaved blonde (so you can see the perforations) pre-pubital hair (no fatty acids that prevent growth of the fungus) cut into short pieces (1cm)
Sterile distilled water 5 ml in a suitable vial.
Place hair in water in vial.
Inoculate with small fragments of the test fungus.
Incubate at room temperature.
Individual hairs are removed at intervals up to 4 weeks and examined microscopically in lactophenol cotton blue. Isolates of T. mentagrophytes produce marked localised areas of pitting and marked erosion whereas those of T. rubrum do not.