Skin scrapings versus standardized skin surface biopsy to detect Demodex mites in patients with facial erythema of uncertain cause – a comparative study.
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Date
2016-09
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Abstract
Background: Standardized skin surface biopsy (SSSB) is considered to be the gold standard
technique to evaluate the density of Demodex mites for the diagnosis of demodicidosis.
Potassium hydroxide (KOH) preparation of skin scrapings is a much simpler procedure
that can be used to detect pathogens in the superfi cial skin. Objective: To evaluate the
reliability of potassium hydroxide preparation of skin scrapings as compared to the standard
skin biopsy technique with regard to capacity to detect Demodex mites, time consumed and
technician satisfaction. Methods: One hundred outpatients presenting with facial erythema
of uncertain cause were enrolled. Standardized skin surface biopsy and potassium hydroxide
preparation of skin scrapings were undertaken in adjacent areas on the patients’ right cheek.
Limitation: Patients with normal facial skin were excluded from the study. Results: The
accuracy of Demodex mite detection by potassium hydroxide preparation of skin-scrapings when
compared to the standard procedure is 82%. The sensitivity, specifi city, positive and negative
predictive values of this method are 75%, 84.2%, 60% and 91.43%, respectively. There was no
statistically signifi cant difference between the standard and skin scraping techniques (P = 0.238)
with regard to mite detection. Mean preparation time while using the skin scraping technique
was 6 times less than that of the standard technique. For interpretation also, skin scraping
technique (3.6 min) consumed much less time than the biopsy technique (9.8 min). Moreover,
experienced technicians were more satisfi ed with skin scraping. Conclusion: Potassium
hydroxide preparation of skin scrapings is an effective, time saving and practical technique to
detect Demodex mites with accuracy comparable to the standard biopsy method.
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Keywords
Demodex mites, demodicidosis, skin scraping technique, standardized skin surface biopsy
Citation
Bunyaratavej Sumanas, Rujitharanawong Chuda, Kasemsarn Pranee, Boonchai Waranya, Muanprasert Chanai, Matthapan Lalita, Leeyaphan Charussi. Skin scrapings versus standardized skin surface biopsy to detect Demodex mites in patients with facial erythema of uncertain cause – a comparative study. Indian Journal of Dermatology, Venereology and Leprology. 2016 Sept-Oct; 82(5): 519-522.