Clinico-mycological study and comparison of efficacy of three different techniques of sample collection from skin lesions for potassium hydroxide mount preparation in dermatophytoses
Keywords:Standard scraping method, Cellophane tape method, Skin surface biopsy
Background: Dermatophytoses are superficial fungal infections which invade and multiply within keratinized tissue. The KOH mount is one of the useful procedures and believed to be more reliable than culture for demonstrating dermatophytes. A few studies in the past have demonstrated the usefulness of alternative methods of sample collection for KOH preparation, but data on sensitivity and specificity of these methods is lacking. The aim of the study was to study the clinic-mycological aspects of dermatophytoses and to compare the efficacy of three different sampling techniques from skin lesions and correlating KOH mount with culture results.
Methods: 210 clinically diagnosed patients with dermatophytic infection attending outpatient department of Dermatology of a tertiary care hospital for duration of 2 years (September 2015 to October 2017) were included. The samples were collected from skin, hair and nail. These samples were used for direct microscopy by KOH mount and fungal cultures by Sabouraud dextrose agar media.
Results: Of the total of 210 patients, maximum were in age group of <10 years (74 cases), male: female - 1.2:1. Tinea corporis was commonest presentation (40.5%). Overall direct microscopy positivity was 81% while three different techniques from the glabrous skin and groins lesions was scraping method (97%), cellophane tape method (96%), skin surface biopsy (SSB) (98%) and culture in (89%). T. rubrum was commonest species isolate (37.7%).
Conclusions: Tinea corporis was the commonest clinical type followed tinea capitis. T. rubrum were commonest dermatophytes isolated. All three methods of sampling were suitable for routine sample collection. The KOH mount helped rapid confirmation of clinical diagnosis.
Bindu V, Pavithran K. Clinico-Mycological study of dermatophytosis in Calicut. Indian J Dermat Venereol Leprol. 2002;68:259-61.
Sentamilselvi G, Kamalam A, Ajithadas K, Janaki C, Thambiah AS. Scenario of chronic dermatophytosis. An Indian study Mycopathologica. 1997;140:129-35.
Mehta JP, Deodhar KP. A study of dermatophytes in Bombay. Indian J Pathol Microbiol. 1977;20:23.
Belukar DD, Barmai RN, Karthikeyan S, Vadhavkar RS. A mycological study of dermatophytosis in Thane. Bombay Hospital J. 2004;46:2.
Barbhuiya JN, Das SK, Ghosh A, Dey SK, Lahiri A. Clinico mycological study of superficial fungal infection in children in an urban clinic in Kolkota. Indian J Dermatol. 2002;47(4):221-3.
Sardari L, Sambhashiva RR, Dandapani R. Clinico mycological study of dermatophytes in a coastal area. IJDVL. 1983;49:2:71-5.
Grover SCW, Roy PCL. Clinic mycological profile of superficial mycosis in a hospital in North East India, MJAFI. 2003;59:114-6.
Sodera OJ, Elewski EB. Fungal diseases. In: Bolognia LJ, Jorizzo LJ, Rapini RP editors. Dermatology. 2nd end. Okhla: Elsevier; 2009: 1135-1164.
Kanwar AJ, Mamta, Chander J. Superficial fungal infections in: Valia GR editor. IADVL text book and Atlas of Dermatology 3rd ed. Mumbai:Bhalani Publishing House; 2007: 215-258.
Singh S, Beena PM. Profile of dermatophyte infections in Baroda. Indian J Dermatol Venereal Lepro. 2003;69:281-3.
Rani V. Study of dermatophytoses in Punjabi population. Ind J Pathol Microbiol. 1983;26(4):243-7.
Alsogair SM, Moawad MK, Al-Humaidan YM. Fungal infection as cause of skin disease in the eastern province of Saudi Arabia prevailing fungi and pattern of infection. Mycosis. 1991;34:337.
Dogra S, Narang T. Emerging atypical and unusual presentations of dermatophytosis in India. Clin Dermatol Rev. 2017;1:12-8.
Karmakar S, Kalla G, Joshi KR, Karmakar S. Dermatophytoses in a desert district of Western Rajasthan. Indian J Dermatol Venereol Leprol. 1995;61:280-3.
Rudramurthy SM, Shaw D. Overview and update on the laboratory diagnosis of dermatophytosis. Clin Dermatol Rev. 2017;1:3-11.