Comparison of diagnostic methods in the diagnosis of dermatomycoses and onychomycoses

Abstract

Direct microscopic examination of potassium hydroxide (KOH)-prepared specimens is the simplest, cheapest method used for the diagnosis of mycotic infections of the skin. However, KOH preparations have been reported to have 5-15% of false-negative results, possibly because of the low visibility of scant, scattered fungal material of the nail scrapings and because the detection of fungal elements depends on the skill of the observer [Arch Dermatol133 (1997) 1317; Clin Microbiol Rev8 (1995) 240]. We compared two different KOH-based staining methods in order to obtain reliable results in shorter time than expected for cultures. A total of 124 patients with suspect diagnosis of dermatomycosis or onychomycosis were enrolled. Two scrapings from the same lesion of each patient were stained with KOH-Chlorazole and KOH-Acridine Orange (AO), respectively; cultural examination of the same specimen was considered as diagnostic gold standard. The two methods showed neither significantly different sensitivity nor specificity; however, for onychomycoses, we observed a slightly higher sensitivity for KOH-Chlorazole and a higher specificity for KOH-AO. We suggest the use of both techniques in order to improve detection of fungal infection, especially for onychomycoses.

Concordance between direct microscopy and fungical culture for the diagnostic of feet's onychomycosis

“…However, none of them was methodologically designed to detect false-negative and falsepositive results. [1][2][3][4][5][6][7] This can mask a more detailed assessment of the potential use of mycological culture as golden standard test for the diagnosis of onychomycosis. [8][9] The objective of this prospective study is to determine the concordance between the direct microscopic examination (DME) and the culture for fungi on the diagnosis of onychomycosis of the feet.…”

New Contrast Stain for the Rapid Diagnosis of Dermatophytic and Candidal Dermatomycoses

“…2 The procedure of obtaining skin surface biopsy specimens followed by staining 3 is more complicated and less suitable for obtaining samples from interdigital webs because of the anatomy. Chlorazol-KOH testing is 60% sensitive and 71.9% specific, 4 but the compound may be a carcinogen. Potassium hydroxide-acridine orange staining has a sensitivity of 61.7% and specificity of 67.2%, 4 and testing with calcofluor white with KOH is 92% sensitive and 95% specific, 5 but both require a fluorescent microscope.…”

KEDİ ve KÖPEKLERDEN DERMATOFİTLERİN İZOLASYONU

“…Ekim yapılan besiyerleri 2-4 hafta arasında inkübasyona bırakılır ve üreyen mantarların mikroskobik ve makroskobik morfolojileri incelenir. Bazen üreaz aktivitesi gibi biyokimyasal veya in vitro saç penetrasyon testi gibi fizyolojik testlerin uygulanması gerekebilir (12,27,33).…”