Clinical spectrum in microbiologically proven Demodex blepharokeratoconjunctivitis: An observational study

Abstract

Purpose: To study the demographic, clinical, and microbiological profile of Demodex-related blepharokeratoconjunctivitis (BKC) at a tertiary eye care hospital.

Methods: This retrospective observational study was conducted from January 2016 to September 2022. It included 83 patients with microbiologically proven Demodex BKC who presented to the cornea department of our tertiary care eye center. The clinical, microbiological, and demographic data of the 83 cases were analyzed.

Results: Of the 83 cases, 57 (68.67%) were younger than 40 years, and 25 (30.12%) were below 20. Most patients presented with a good visual acuity of 20/40 or better (93 eyes; 84.55%). The disease was unilateral in 55 patients and bilateral in 28. Cylindrical dandruff was the predominant presentation noted in 61 eyes (54.95%), followed by corneal scarring in 47 eyes (42.34%) and corneal vascularization in 40 eyes (36.04%). On light microscopy, 87.95% of the positive samples were identified as Demodex folliculorum , 7.23% as Demodex brevis , and 6.02% remained unidentified. Tea tree oil and lid scrubs eradicated the disease in most patients clinically (75/83, 90.36%).

Conclusion: The spectrum of BKC includes both lid signs and corneal involvement. It can be a cause of recurrent BKC and detection of the mite by microscopic evaluation of the lashes can confirm the diagnosis. In most cases, the tea tree oil can effectively manage this condition. However, low doses of topical steroids are needed to control the inflammation in patients with corneal involvement.

Figure 1

(a-c) Slit lamp photograph of the lashes in Demodex blepharitis, showing classical collarettes and cylindrical dandruff-like deposits. The lid margin appears ulcerated and erythematous in c. (d-f) Slit lamp photograph of the corneal findings; d shows large area of diffuse anterior stromal with superficial vessels. e shows corneal scarring with a leash of vessels f shows corneal scarring and focal area of thinning with regressing/ghost vessels

Figure 2

(a and b) Eyelash with Demodex folliculorum larvae under light microscopy (c) Eyelash with Demodex brevis larvae under light microscopy