ONYCHOMYCOSIS IN HONG-KONG

Background Onychomycosis in temperate countries has been studied exten sively, but few data are available on its epidemiology in tropical cou ntries. We performed a survey of patients seen in Hong Kong for the 8- year period from January 1987 to December 1994. Methods A retrospectiv e study of the mycology laboratory records of patients attending the G overnment Dermatology Clinics was carried out. Nail samples examined i ncluded clippings, scrapings, and drillings. Microscopy was performed on all specimens. Sabouraud dextrose agar was used for culture. Result s Out of a total of 2382 nail samples (1024 (43.0%) toe, 1148 (48.2%) finger, and 210 (8.8%) unspecified site) examined, 340 (14.3%) were mi croscopy positive; 165 (48.5%) of these were culture positive, includi ng 160 (97%) with dermatophyte and/or yeast, and 5 (3%) with molds, Me n were affected more in the <19 and >50 years age groups, whereas wome n were affected more in the 20-50 years age group. Women were affected significantly more than men with yeasts, dermatophytes occurred more during adolescence. Dermatophytes showed a high peak in late spring, a lthough both dermatophyte and yeast cases peaked in the summer months. Dermatophytes (29.1%) occurred more commonly than yeasts (19.4%) in m icroscopy-positive onychomycosis cases in Hong Kong, Trichophyton rubr um was the commonest dermatophyte, and Candida spp., other than C. alb icans, were the commonest yeasts, Mixed infections (5%) were uncommon. Conclusions Dermatophytes are more important than yeasts as a cause o f onychomycosis in Hong Kong, Changes in climatic conditions affect th e prevalence of dermatophytes more than yeasts.