Topical permethrin alleviates symptoms, parasite load in Demodex-associated blepharitis

This prospective trial evaluated the safety and efficacy of permethrin cream for the treatment of Demodex blepharitis.

Study design

Researchers enrolled 21 patients with blepharitis and coexisting Demodex as identified by light microscopy and cylindrical dandruff. Patients were treated for 6 months with permethrin 5% cream applied once daily to the eyelashes, eyelids and eyebrows; eyes were kept closed for 30 seconds after administration. Ocular examination, Demodex counts, Ocular Surface Disease Index (OSDI) and a blepharitis symptom questionnaire was used to evaluate the patient at each follow-up visit.

Outcomes

The authors observed a drop in Demodex counts and a consistent decrease in parasite load throughout the entire treatment period. Blepharitis symptom scores improved, which included feeling of dry eye, discharge and formation of dandruff-like debris. Overall, blepharitis symptoms score improved from 42.9 to 32.7 (P=0.011). Clinical examination demonstrated a decrease in scaling and corneal staining with fluorescein. There were no adverse events.

Limitations

This study did not enroll a control group and the patients and examiner were not masked to the treatment. Only 5 patients returned for the 6-month follow-up so final treatment outcome is unknown. Ex vivo Demodex eyelash counts may not be representative of complete parasite burden.

Clinical significance

Blepharitis and Demodex-related eyelid disease can be difficult to treat. The insecticide permethrin cream was effective in reducing parasite burden and improving symptoms of blepharitis without adverse side effects. Future studies are needed to determine the ideal treatment schedule and duration.