Comparison of Efficacy of Slit Skin Smear and Fite Faraco Stain on Histopathology Specimens in Cases of Leprosy WC01-WC04
Dr. Aishwarya Bhalchandra Patil,
Resident, Department of Dermatology, Venereology and Leprosy, Datta Meghe
Institute of Medical Sciences, Sawangi [Meghe], Wardha-442004, Maharashtra, India.
Introduction: Hansen’s disease is an infectious granulomatous disorder with Mycobacterium leprae being the causative agent. Mycobacterium Leprae is an acid-fast bacillus which grows slowly inside host cells mainly neural Schwann cell as well as cutaneous macrophages.
Aim: To study the efficacy of Slit Skin Smear (SSS) and Fite Faraco stain on histopathology for diagnosis in leprosy.
Materials and Methods: The present cross-sectional study carried out on patients clinically diagnosed as Leprosy attending dermatology OPD in AVBRH, Sawangi, Wardha, Maharashtra, India from sepetember 2017 to August 2019. A total of 88 patients who gave informed consent to participate in study and their clinical features were recorded including number, size and location of lesions and loss of sensation. Any contiguous cutaneous nerve or peripheral nerve trunk enlargement was noted and were classified according to the Ridley-Jopling Classification. SSS and Fite Faraco stain on histopathology specimens was done. The quantitative variables were compared using Kruskal Wallis Test and qualitative variables were correlated using Chi-square test/Fisher’s-Exact test.
Results: Out of 88 (n=88) clinically diagnosed leprosy cases enrolled in this study, 2, 17, 15, 6, 20, 25 and 3 cases were diagnosed as indeterminate, Tuberculoid Leprosy (TT), Borderline Tuberculoid Leprosy (BT), Mid Borderline leprosy (BB), Borderline Lepromatous Leprosy (BL), Lepromatous Leprosy (LL) and pure neural leprosy, respectively. Mycobacterium leprae detection by SSS was possible in 21.59% cases while detection by Fite Faraco staining on tissues sections was possible in 11.36% cases. There were 10 (11.36%) cases in which Mycobacterium leprae was detected by SSS but not by Fite Faraco, while in 7 (7.95%) cases. Mycobacterium leprae was detected by Fite Faraco staining but not by slit skin smear microscopy. The difference in detection by the two methods was found statistically significant with p-value 0.002. On comparison-slit skin smear had sensitivity of 26.47% whereas Fite Faraco had 23.53%. The specificity Fite faraco staining was 100% while that of SSS was found to be 95%.
Conclusion: On comparison of efficacy of SSS and Fite faraco staining on tissue sections, SSS had the highest detection rate and sensitivity in diagnosing leprosy whereas Fite Faraco was found to be more specific.