Демодекоз (Demodex), соскоб

Microscopic examination for Demodex spp. (eyelash mites microscopy) is used to document ocular demodicosis and demodectic blepharitis by identifying mites on epilated eyelashes or lid-margin scrapings. The eyelash test for Demodex supports the differential diagnosis of blepharitis when symptoms persist despite standard care and is also used to track response after therapy directed at reducing mite burden.

Demodex mites are ectoparasites that inhabit or lie near hair follicles. In humans, Demodex folliculorum and Demodex brevis predominate and are most often found on the face—around the nose, forehead, chin, eyelashes, and eyebrows. Adults measure approximately 0.3–0.4 mm. After mating, females deposit eggs within a hair follicle or sebaceous gland, and a single follicle may harbor up to 25 mites. They move at roughly 8–16 mm per hour with activity that increases at night. Colonization is widespread, with detection in about half of adults; some reports describe near‑universal detection in individuals older than 70 years. Transmission occurs through close direct contact involving hair, brows, or sebaceous secretions. Most colonization remains asymptomatic. Clinical demodicosis is more likely with impaired immune function, metabolic disturbances, or hormonal imbalance. Demodex has been linked to certain forms of rosacea and to treatment‑refractory blepharoconjunctivitis in children. Manifestations include pruritus, inflammation, and facial eruptions. In demodectic blepharitis, patients may report intense itching that worsens toward evening, a sensation of heaviness in the eyes, eyelid erythema and inflammation, and scant ocular discharge. Examination can reveal scurf or collarettes along the lid margin, crust‑related lash agglutination, possible eyelash loss, lid thickening, and meibomian gland dysfunction; secondary conjunctivitis may occur, and vision can decline in advanced disease. Diagnosis is established by microscopy of epilated eyelashes, and other etiologies of blepharitis should be considered. Management typically employs specialized eyelid oils, ointments, and gels; adherence to therapy reduces mite counts and mitigates symptoms.