PREVALENCE AND EPIDEMIOLOGY OF UNSUSPECTED ONYCHOMYCOSIS IN PATIENTS VISITING DERMATOLOGISTS OFFICES IN ONTARIO, CANADA - A MULTICENTER SURVEY OF 2001 PATIENTS

Background Questionnaire studies have been used to determine the preva lence of onychomycosis in the United Kingdom and Europe. One disadvant age of this methodology is that the patient self-diagnoses the onychom ycosis. There have been very few large studies involving clinical exam ination of the nails of subjects, followed by mycological confirmation of the onychomycosis, We therefore determined the prevalence of onych omycosis in patients visiting dermatologists' offices in Ontario, Cana da. Methods In a prospective, multicenter study, the finger-and toenai ls of all new patients presenting to dermatologists' offices were exam ined by a board-certified dermatologist. If there was clinical suspici on of onychomycosis, then nail samples were obtained for mycological e xamination at a central laboratory. Patients referred specifically for the management of onychomycosis were excluded. Results Toenails appea red abnormal in 455 (22.7%) of 2001 patients. Mycologically-confirmed pedal onychomycosis was present in 182 (9.1%) of the 2001 patients. Th e estimated value of the prevalence of onychomycosis in Ontario is 6.8 6% (95% confidence interval (CI), 5.8-8.0%), when corrected for age an d sex of the general population using census data, Onychomycosis incre ased with age (P < 0.0001). The odds of males having onychomycosis was 84.3% greater than females of the same age (P = 0.0003). The distribu tion of organisms in the 141 patients with pedal onychomycosis who wer e culture positive was: dermatophytes 131 (92.9%), Candida species 4 ( 2.8%) and non-dermatophyte molds 6 (4.3%). Conclusions The prevalence of mycologically-confirmed toenail onychomycosis was 9.1%, with the es timated prevalence in Ontario being 6.86%, The majority of patients wi th abnormal-appearing nails were unaware they might have onychomycosis , that it is infectious and potentially treatable, suggesting that the re is potential for increased public awareness and education.