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.

Hair perforation test.

Positive hair perforation test.