Association Between Demodex Infestation and Severe Acne Vulgaris: A Cross-Sectional Study of 168 Patients. / Asociación entre la infestación por el Demodex sp. y el acné vulgar grave. Estudio transversal de 168 pacientes.

ABSTRACT

BACKGROUND AND OBJECTIVES: Infestation with Demodex mites has been associated with acne vulgaris. The aim of this study was to explore the association between Demodex infestation and severe acne vulgaris in outpatients seen at Hospital Regional Lambayeque in Chiclayo, Peru. MATERIAL AND METHODS: We conducted a cross-sectional study of 46 patients with severe acne and 92 patients with nonsevere acne. Severe acne vulgaris was diagnosed if the score was 3 or more on the Spanish Acne Severity Scale (EGAE, in its Spanish acronym). Demodex infestation was diagnosed when a skin surface biopsy showed more than 5 mites/cm2. RESULTS: The patients had a median age of 18 years (interquartile range, 15-20 years), 60.9% were male, 81.9% lived in an urban area, and 29.7% were infested with Demodex mites. In the bivariate analysis, severe acne vulgaris was significantly associated with Demodex infestation (P=.001), sex (P=.003), residence (P=.015), a paternal history of acne (P=.045), a maternal history of acne (P=.045), and type of skin (P<.001). In the multivariate analysis, after adjustment for male sex, urban residence, previous treatment, maternal and paternal history of acne vulgaris, and an oily skin type, patients with Demodex infestation were 4.2 times more likely to have severe acne vulgaris (95% CI 1.6-10.9, P=.003). CONCLUSION: Demodex infestation was associated with severe acne vulgaris in outpatients at our hospital.