Dermatophyte

Abstract: Background: Onychomycosis, a fungal infection of the nail bed, is responsible for up to 50% of nail disorders. Although several surveys have been conducted in different parts of the world, there have been no multicenter epidemiologic surveys of onychomycosis in North America. Objective: A 12-center study was undertaken to (1) determine the frequency of onychomycosis, (2) identify organisms recovered from the nails, and (3) determine the antifungal susceptibility of isolates. Methods: A total of 1832 subjects participated in this study and completed a comprehensive questionnaire, and nail clippings were collected for potassium hydroxide examination and culturing. Results: The frequency of onychomycosis, as defined by the presence of septate hyphae on direct microscopy and/or the recovery of a dermatophyte, was found to be 13.8%. In general, the dermatophyte isolates were susceptible to the antifungals tested. Conclusion: Because of the limited number of large-scale studies, the baseline incidence is not firmly established. However, the higher frequency of onychomycosis in this study may confirm the suspected increase in incidence of disease in North America. (J Am Acad Dermatol 2000;43:641-8.).

Abstract: The spectrum of dermatophytes isolated from skin lesions had changed in last 70 years Before the Second World War in Germany, Microsporum audouinii and Epidermophyton floccosum ranked the first, whereas Trichophyton rubrum is the most common dermatophyte since the fifties of last century, accounting for 80-90% of the strains, followed by T mentagrophytes This evolution is typical for Central and North Europe and it needs to be connected with the increase in the incidence of tinea pedis In contrast, in Southern Europe and in Arabic countries, zoophilic dermatophytes, such as Microsporum canis or Trichophyton verrucosum, are the most frequently isolated In Europe, especially in Mediterranean countries, the incidence of M canis infection has strongly increased during the recent years and this dermatophyte is now the most prevalent in tinea capitis in children An analysis of the frequency and distribution of tinea pedis in different occupations and leisure-time activities as well as the routes of infection are reported The spreading of this disease in most developed countries of the world represents a considerable economic problem, since it was accompanied by a parallel increase in the frequency of onychomycosis which implies, as tinea pedis, large financial charges In poor developing countries, mycoses appear endemically, primarily with children, and their treatment often fails because of the lack of efficient antifungals The particular epidemiological situations of dermatophytoses and the pathogenic spectrum of dermatophytes are examined at the example of numerous countries

Abstract: A prospective, multicenter study to determine the epidemiology of onychomycosis was performed in the offices of 3 dermatologists and 1 family physician in Ontario, Canada. In the sample of 15,000 patients, abnormal-appearing nails were observed in 2505 persons (16. 7%). There were 1199 patients (8%) with toenail or fingernail onychomycosis confirmed on mycologic examination, with 1137 patients (7.6%) who had only pedal onychomycosis, 40 patients with toenail and fingernail onychomycosis (0.27%), and 22 patients (0.15%) with only fingernail onychomycosis. The condition was more common in male patients (P or =75% nail involvement) in 27.6%, 39.9%, and 32.5% of patients, respectively. After adjusting for the age and sex distribution of the general population, the projected rate of onychomycosis in Canada is 6.5% (95% confidence interval [CI], 6. 1%-6.9%). The organisms causing toenail onychomycosis were 90.5% dermatophyte, 7.8% nondermatophyte molds, and 1.7% Candida spp. The corresponding organisms causing fingernail onychomycosis were 70.8%, 0%, and 29.2%, respectively. In a large sample of 15,000 patients, abnormal-appearing nails were present in 17% of the sample with mycologic evidence of toenail or fingernail onychomycosis in 8%. The projected prevalence of onychomycosis in Canada is 6.5% (95% CI, 6. 1%-6.9%).

Abstract: During the past 50 years, the predominant etiologic agent of tinea capitis in the United States and in Western Europe has changed from Microsporum audouinii to Trichophyton tonsurans . This is thought to be due in part to the sensitivity of M audouinii to griseofulvin treatment and, in part, due to the importing of T tonsurans by people emigrating from geographic areas where that vector had been the prominent cause of tinea capitis. With these changes, prospects for newer therapies with the novel antimycotic agents itraconazole, fluconazole, and terbinafine are reviewed. (J Am Acad Dermatol 2000;42:1-20.) Learning Objective: At the conclusion of this learning activity, participants should be familiar with the history, epidemiology, and current knowledge of tinea capitis, as well as the newer antifungal agents (ie, itraconazole, fluconazole, and terbinafine) to treat this infection.