[Histologic studies on otomycosis].

Fungal infections of the ear are mostly described as mycoses of the auditory canal. The aim of our investigations was to find out how fungi colonize the ear in immunocompetent patients. In the years from 1993 to 2000, 128 patients suspected of having otomycosis were examined. Of these 115 patients suffered from chronic otitis media with persisting tympanum perforation and otorrhea. A further 13 patients had clinical signs of otitis externa only. In 54 out of 139 samples, fungi were found in the auditory canal, in five on the tympanic membrane, and in five in the middle ear. Two-thirds were isolated as moulds and one-third as yeasts. Dominating species were Aspergillus niger and Candida parapsilosis. Samples of 15 patients suspected of having mastoiditis or cholesteatoma were examined histologically. Fungal hyphae were observed in the middle ear cavity and/or between horny lamellae of cholesteatoma in 4 patients. In the middle ear of immunocompetent patients chronic-hyperplastic (polypous) inflammation was detected with increased production of mucus, which probably promotes the colonization with pathogenic fungi as in the middle ear just like in the auditory canal.