The prevalence and intensity of Demodex folliculorum and D. brevis (Acari: Demodicidae) in patients with Ocular dandruff

Demodex mites (Acari) are micro-arthropod microorganisms belonging to the family Demodicidae. Two species of these mites have been identified in humans: Demodex folliculorum and D. brevis. Today, it is thought that the mites that attract the attention of ophthalmologists are important in the pathogenesis of eyelid diseases such as cylindrical, sporadic and diffuse dandruff. The follicular epithelial cells and sebum are the main nutritional source of these mites. They have a number of enzymes and several mouth parts to permeate the follicular epithelial cells. The follicular cell wastes formed due to the feeding of the mites are pushed to the follicle surface. As a result, these wastes accumulate at the base of the lashes and form dandruff. This study was performed to determine the prevalence and intensity of Demodex spp. in patients with ocular dandruff. A total of 186 patients with ocular dandruff and 183 healthy controls were included in the study. Personal care and hygiene practices, demographic characteristics and skin biophysical parameters of these participants were recorded, and samples were taken from the facial areas (eyelash, eyebrow and cheek). In the study, Demodex positivity was detected in 90.3% of the cylindrical dandruff patients (mean 38.39) and 83.1% of the controls (mean 21.86). When the skin biophysical properties were taken into consideration, the density of Demodex was higher in the participants wich having low moisture and temperature values and high pH values. On the other hand, Demodex positivity and density were increased with age increase in the participants. As a result, it was determined that the most common ocular complaints were itching and foreign body. Demodex mites were found to be very common and intense in the patients with ocular dandruff. It was considered that it would be useful to take into account Demodex mites in the clinical evaluation and treatment of these patients.