Background: Blepharoconjunctivitis is the commonest manifestation of ocular rosacea. Cilia epilation proves Demodex folliculorum, considered an etiologic factor in rosacea. Complications and differential diagnosis include dry eyes, seborrheic, bacterial and allergic blepharoconjunctivitis. Treatment involves lid scrubs and mercury ointment, its duration is limited to 6 weeks under frequent control due to corneal toxicity of mercury.
History and signs: 30-year-old female with complaint of red, irritated eyes for 21 years, resistant to antibiotics and antiallergics. General medical history unremarkable, mercury allergy. Acuity: R/L 20/20. Biomicroscopy: red, thickened eyelid margins, crusty debris on rarefied, partially broken lashes, conjunctival telangiectasia, low tear meniscus, further ophthalmologic examination unremarkable.
Diagnosis: chronic Demodex blepharoconjunctivitis.
Therapy and outcome: Conventional treatment was contraindicated due to mercury allergy. Alternative oral minocycline 100 mg daily brought no subjective nor objective relief. Combination of lid scrubs and 2% Metronidazole gel relieved symptoms and halved number of mites after 1 month, lashes grew again after 2 months. Treatment was discontinued after 6 months as Demodex folliculorum proof remained negative. No relapse occurred during 1 year.
Conclusions: Topical Metronidazole 2% proved to be an effective treatment of chronic Demodex blepharoconjunctivitis in our case and thus may offer a new and save alternative to existing therapies. Neither ocular nor systemic side effects occurred. Controversial theories on the aetiology of blepharitis are discussed.