Evaluation of the incidence of Demodex in eyelashes in rosacea patients with ocular involvement

Evaluation of the incidence of Demodex in eyelashes in rosacea patients with ocular involvement. Abstract Background and Design: Demodex, a mite, is known to influence the etiopathogenesis of rosacea, pityriasis folliculorum, pustular folliculitis, perioral granulomatous dermatitis, hyperpigmented patch, and chronic blepharitis. This study aimed to investigate the relationship between Demodex, which is increasingly important in the pathogenesis of rosacea, and ocular rosacea. Materials and Methods: A total of 103 rosacea patients with ocular involvement (ocular rosacea) and 140 volunteers without facial dermatosis were included in the study as the control group. Written and verbal consent was obtained from the participants. A total of five eyelashes were pulled from the upper and lower eyelids of one or both eyes of the patient group and control group, using forceps, and the presence of Demodex was examined by the epilation method and standard superficial skin biopsy method from the face. Under a light microscope, ≥ 1 and ≥ 5 Demodex per cm 2 in the eyelashes and face were evaluated as positive, respectively. Results: Of the 103 patients, 27 (26.2%) had conjunctivitis, 77 (74.8%) had blepharitis, 1 (1%) had hordeolum, and 24 (23.3%) had meibomian gland dysfunction. The eye examination findings of the control group were normal. The Demodex incidence rates were 84.5% and 29.3% in the patient group and control group, respectively. Of the 103 patients with rosacea accompanied by ocular rosacea, Demodex mites were present in the eyelashes and face of 51 patients (49.6%), only in the eyelashes in 26 (25.2%), and only in the face in 10 (9.7%). No Demodex mites were present on both eyelashes and face in 16 (15.5%) patients. Conclusion: The results of this study show that Demodex positivity was detected at a higher rate in the eyelashes and face in patients with rosacea compared with the controls. Demodex may play an important role in the pathogenesis of rosacea and ocular rosacea.