Comparison of Skin Scraping and Standard Superficial Skin Biopsy in the Laboratory Diagnosis of Scabies

Objective: Scabies is diagnosed based on the presence of burrows on the skin, Sarcoptes scabiei adult, egg, or scybala in skin scrapings. The laboratory diagnosis of scabies poses various challenges. We aimed to compare the analytical performance of skin scraping and standard superficial skin biopsy (SSSB) and to investigate the correlation with false negative results in the laboratory diagnosis of scabies.

Methods: Skin scraping and SSSB were applied from July 1 to December 31, 2018 on 42 patients whose burrows were marked using dermatoscopy, as obtained from the laboratory information system.

Results: The number of patients who tested positive for scabies with skin scraping was 18 (42.9%) and 24 (57.1%) with SSSB, and the difference was significant (p=0.003). Sensitivity was 42.9% for skin scraping and 57.1% for SSSB. The number of positive cases with both techniques was 15 (35.7%). The number of patients positive with only skin scraping was 3 (7.1%) and only SSSB was 9 (21.4%).

Conclusion: To date, it has seemed impossible to diagnose scabies using a single clinical or laboratory test. According to our results, SSSB is an inexpensive and easy-to-apply method with high sensitivity for obtaining skin samples for scabies laboratory diagnosis.