STANDARDIZED SKIN SURFACE BIOPSY - A BETTER DIAGNOSTIC OPTION FOR DEMODICOSIS IN MACULAR ROSACEA IN VIETNAMESE PATIENTS

Abstract

Introduction: Demodicidosis is a chronic skin disease, caused by two species of Demodex (D.
folliculorum and D. brevis). Demodex infected individuals are mainly symptomless and may have
pathogenic symptom only when mite density is high within the skin.
Objectives: To compare the value of the Standardized skin surface biopsy (SSSB) and direct
microscopic examination with KOH (DME) for assessing Demodex density.
Methods: Fifty patients with demodicosis were determined Demodex by SSSB and DME.
Comparision of the similarity of test results between the two methods was conducted by Cohen’s
Kappa statistic.
Results: The positive test rate of SSSB is 90.0%, of DME is 82.0%. The percentage of patients who
tested positive for both methods was 76.0%, and the negative for both methods was 4.0%. Demodex
density > 5/cm2
of SSSB was 47.9% higher than DME of 29.2%. There was quite similarity of Demodex
density between SSSB and DME with coefficient kappa = 0.62.
Conclusion: SSSB is more sensitive method for detecting Demodex than DME, particularly in patients
with macular lesions, vasodilatation, U-shaped distribution, located on the nose and nasolabial sulcus.

Received: 19/04/2022
Revised: 21/05/2022
Accepted:  10/06/2022