MICROSCOPIC DIAGNOSIS OF ONYCHOMYCOSIS

Introduction. The microbiological identification of onychomycosis may be uncertain as some fungi growing in culture from this material are n ot necessarily pathogen and invasive. Conversely, the negativity of a culture is not rare even when fungi are seen by microscopy. Materials and methods. We compared the information brought by standard histologi cal examination, immunohistochemistry and in vivo confocal microscopy. Results. The histological examination of nails is of importance in th is pathology. We present a laboratory technique that proves to be easy and rapid. We report diagnostic criteria allowing the distinction bet ween dermatophytes, yeasts and non-dermatophyte molds. The standard mi croscopic examination may further be improved by immunohistochemistry using some antibodies to fungi. In vivo confocal microscopy is a techn ique for the future. The dermatologist will be able to see fungi in th e nail at the clinical examination, without any sampling or peculiar p reparation. Conclusion. The histological examination is a routine tech nique useful for defining the nature and localization of fungi in the nail plate. Immunohistochemistry applied to onychomycosis is an experi mental approach bringing prominent informations about the identificati on of fungi. In vivo confocal microscopy is a door opened to the futur e.