[Microscopic diagnosis of onychomycoses].

INTRODUCTION

The microbiological identification of onychomycosis may be uncertain as some fungi growing in culture from this material are not 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 histological examination, immunohistochemistry and in vivo confocal microscopy.

RESULTS

The histological examination of nails is of importance in this pathology. We present a laboratory technique that proves to be easy and rapid. We report diagnostic criteria allowing the distinction between dermatophytes, yeasts and non-dermatophyte molds. The standard microscopic examination may further be improved by immunohistochemistry using some antibodies to fungi. In vivo confocal microscopy is a technique for the future. The dermatologist will be able to see fungi in the nail at the clinical examination, without any sampling or peculiar preparation.

CONCLUSION

The histological examination is a routine technique useful for defining the nature and localization of fungi in the nail plate. Immunohistochemistry applied to onychomycosis is an experimental approach bringing prominent informations about the identification of fungi. In vivo confocal microscopy is a door opened to the future.