EVALUATION OF KOH MOUNT, FUNGAL CULTURE, AND PAS STAINING IN ONYCHOMYCOSIS: A COMPARATIVE STUDY
Main Article Content
Keywords
Culture, Onychomycosis, Periodic acid-Schiff staining, Potassium hydroxide mount.
Abstract
Onychomycosis is a prevalent condition linked to considerable physical and psychological morbidity. The rise in prevalence in recent years can be linked to increased longevity, comorbid conditions such as diabetes, active participation in certain activities, and the emergence of HIV. The study aimed to assess the efficacy of KOH mount, fungal culture, and PAS staining of the affected nail plate in diagnosing onychomycosis. Approach: One hundred ten patients with clinically suspected onychomycosis were selected for the study. Nail scrapings and clippings underwent KOH mount for direct microscopic examination, culture on Sabouraud’s dextrose agar (with and without antibiotics), and histopathologic examination utilising PAS staining (HP/PAS). Results: Direct microscopy with KOH mount, mycological culture, and HP/PAS yielded positive results in 40 (36.36%), 35 (31.81%), and 45 (40.90%) patients, respectively. Fungal infection was confirmed in 45 samples using at least one of the three methods. When using this as the denominator, HP/PAS exhibited a sensitivity of 40.90%, which was significantly greater than that of KOH mount (36.36%) or mycological culture (31.81%). In conclusion, histopathologic diagnosis utilising PAS staining of nail clippings demonstrated the highest sensitivity among the tested methods. The procedure was straightforward, efficient, and resulted in markedly higher detection rates of onychomycosis compared to standard methods, specifically KOH mount and mycological culture.
References
2. Gupta AK, Versteeg SG, Shear NH. Onychomycosis in the 21st century: an update on diagnosis, epidemiology, and treatment. J Cutan Med Surg. 2017;21:525-39.
3. Maraki S, Mavromanolaki VE. Epidemiology of onychomycosis in Crete, Greece: a 12-year study. Mycoses. 2016;59:798-802.
4. Leung AKC, Lam JM, Leong KF, et al. Onychomycosis: an updated review. Recent Pat Inflamm Allergy Drug Discov. 2020;14:32-45.
5. Lipner SR, Scher RK. Onychomycosis: clinical overview and diagnosis. J Am Acad Dermatol. 2019;80:835-51.
6. Pang SM, Pang JYY, Fook-Chong S, Tan AL. Tinea unguium onychomycosis caused by dermatophytes: a ten-year (2005-2014) retrospective study in a tertiary hospital in Singapore. Singapore Med J. 2018;59:524-7.
7. Summerbell RC, Gueidan C, Guarro J, et al. The protean Acremonium. A. sclerotigenum/egyptiacum: revision, food contaminant, and human disease. Microorganisms. 2018;6:88.
8. Bongomin F, Batac CR, Richardson MD, Denning DW. A review of onychomycosis due to Aspergillus species. Mycopathologia. 2018;183:485-93.
9. Subramanya SH, Subedi S, Metok Y, Kumar A, Prakash PY, Nayak N. Distal and lateral subungual onychomycosis of the finger nail in a neonate: a rare case. BMC Pediatr. 2019;19:168.
10. Ghannoum M, Mukherjee P, Isham N, Markinson B, Rosso JD, Leal L. Examining the importance of laboratory and diagnostic testing when treating and diagnosing onychomycosis. Int J Dermatol. 2018;57:131-8.
11. Karaman BFO, Açıkalın A, Ünal İ, Aksungur VL. Diagnostic values of KOH examination, histological examination, and culture for onychomycosis: a latent class analysis. Int J Dermatol. 2019;58:319-24.
12. Kurade SM, Amladi SA, Miskeen AK. Skin scraping and a potassium hydroxide mount. Indian J Dermatol Venereol Leprol. 2006;72:238-41.
13. Culling RF. Fixation. In: Rachael SS, editor. Lynch medical laboratory and technology. 3rd ed. Philadelphia: W.B. Sanders Company Limited; 1976. p. 886.
14. Elewski BE. Onychomycosis: Pathogenesis, diagnosis and management. Clin Microbiol Rev. 1998;11:415-29.
15. Suarez SM, Silvers DM, Scher RK, Pearlstein HH, Auerbach R. Histopathologic evaluation of nail clippings for diagnosing onychomycosis. Arch Dermatol. 1991;127:1517-9.
16. Adhikari L, Gupta AD, Pal R, Singh TS. Clinico etiological correlates of onychomycosis in Sikkim. Indian J Pathol Microbiol. 2009;52:194-7.
17. Grover C, Reddy BSN, Chaturvedi KU. Onychomycosis and the diagnostic significance of nail biopsy. J Dermatol. 2003;30:116-22.
18. Taniwala R, Sharma K. Current clinic mycological trends in onychomycosis in Pune. Indian J Dermatol. 2012;57:3.
19. Gianni C, Morelli V, Cerri A, Greco C, Rossini P, Guiducci A, Braidotti P, Calcaterra R, Papini M. Usefulness of histological examination for the diagnosis of onychomycosis. Dermatology. 2001;202:283-8.
20. Hajar T, Fernandez-Martinez R, Moreno-Coutino G, et al. Modified PAS stain: a new diagnostic method for onychomycosis. Rev Iberoam Micol. 2016;33:34-7.
21. Shenoy MM, Manjunath T, Teerthanath S, Karnaker VK, Girisha BS, Prasad KM, Pinto J. Comparison of potassium hydroxide mount and mycological culture with histopathologic examination using periodic acid-Schiff staining of the nail clippings in the diagnosis of onychomycosis. Indian J Dermatol Venereol Leprol. 2008;74:226-9.
22. Jung MY, Shim JH, Lee JH, et al. Comparison of diagnostic methods for onychomycosis, and proposal of a diagnostic algorithm. Clin Exp Dermatol. 2015;40:479-84.
23. Begari V, Pathakumari P, Takalkar AA. Comparative evaluation of KOH mount, fungal culture and PAS staining in onychomycosis. Int J Res Dermatol. 2019;5:xxx-xx.
Article Sidebar
Article Details
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
All articles published in JPTCP are licensed under Copyright Creative Commons Attribution-NonCommercial 4.0 International License.
Dr Juhee
Departments of Microbiology, World College of Medical Sciences Research and Hospital, Jhajjar, Haryana, India.
Dr Karuna
Departments of Pathology, World College of Medical Sciences Research and Hospital, Jhajjar, Haryana, India.
Dr Manju
Departments of Microbiology, World College of Medical Sciences Research and Hospital, Jhajjar, Haryana, India.
Dr Priyanka
Departments of Microbiology, World College of Medical Sciences Research and Hospital, Jhajjar, Haryana, India.
Dr Sandeep Kumar
Departments of Biochemistry, World College of Medical Sciences Research and Hospital, Jhajjar, Haryana, India.