Human Demodex mites (Acari: Demodicidae) as a possible etiological factor in Rosacea: A cross-sectional study from Turkey

This study was conducted to determine the prevalence and burden of Demodex mites in patients with rosacea, and to investigate their potential contribution to the aetiology of rosacea. The study included 82 patients (44 with papulopustular rosacea and 38 with erythematotelangiectatic rosacea) diagnosed with rosacea by clinical examination and 82 healthy controls without dermatologic disease. Samples were obtained from each participant from the cheek, nasolabial, and chin regions using standardised skin surface biopsy (SSSB). Samples were examined under a light microscope, and Demodex species were identified and counted. Demodex positivity (≥5 mites) was detected in 91% of patients and 20% of controls in the study (p< 0.01). Only D. folliculorum (total 1328, mean 44.27/cm2) was detected in 37% of patients and D. folliculorum + D. brevis coinfection (total 6071, mean 134.91/cm2) in 55% of patients. Only D. folliculorum (total 97, mean 6.06/cm2) was detected in 20% of healthy controls, while D. folliculorum + D. brevis co-infection was not detected. The study showed that Demodex burden in patients with rosacea was approximately 30 times higher than in healthy controls and was caused by coinfection of D. folliculorum and D. brevis (mean Demodex burden: 179.18/cm2 in patients, 6.06/ cm2 in healthy controls). It was concluded that Demodex infestation, especially co-infection with D. folliculorum and D. brevis, may be a potential factor in the aetiology of rosacea that should not be ignored in the clinic, and that it may be appropriate to initiate antiparasitic treatment when the parasite is detected. © 2024 Systematic and Applied Acarology Society. All rights reserved.