EVOLVING ROLE OF NONDERMATOPHYTES IN ONYCHOMYCOSIS

Onychomycosis is the term given to any fungal infection of tbe nail and represents one of the more common superficial fungal infections.' Greater medical attentioti needs to be placed on the identification, evaluation, and management of tbe pathogens that underlie this disease. There is increasing awareness of nail infections. Also, nonpathogenic fungi, not normally associated with nail disease, may be emerging as pathogens by taking advantage of the impaired resistance of many of today's patients. In particular, a number of species of yeast in the genus Candida have been described as the etiologic agents of dystrophic nails and cases of nondermatophytic molds have been documented as nail pathogens. Likewise, the increasing frequency of mixed infections, from which dermatophytes, yeasts, and/or molds, or a combination thereof have been isolated, has important implications for the future management of onychomycosis;-^"'' however, one should remember, that the mere isolation of an organism from an infection site is not proof that it is the causative pathogen. Thus, although for many years yeasts and molds have been cultured from nails, they have been considered either contaminants or commensals and, therefore, ignored as the etiology of nail disease. A positive potassium hydroxide (KOH) preparation, showing byphae, pseudobyphae, or yeast, is needed to prove a fungal etiology. Histopathological examination showing invasion of the fungus in a nail plate will positively confirm the etiology. Accumulating diagnostic evidence suggests that nondermatophytes can no longer be discounted as a potential cause of nail disease.