High Prevalence of Overlooked Demodex Blepharitis: Unraveling the Challenges in Diagnosis and Treatment

Blepharitis is a common eye condition characterized by eyelid inflammation, redness, and irritation. It's often linked to Demodex mite infestation, but diagnosis can be challenging due to limited treatment options and practical issues with mite visualization. Historically, diagnosing Demodex infestation involved examining epilated eyelashes under a microscope, a method that's uncomfortable and time-consuming. A study aimed to evaluate Demodex blepharitis prevalence in patients visiting US eye clinics for various reasons, including routine exams and eye-related concerns, was published in Clinical Ophthalmology.

The study reviewed over 1,000 case records from 6 eye clinics and found that Demodex blepharitis was present in 57.7% of patients, regardless of their primary reason for the visit. This prevalence rate aligns with findings from studies outside the US, which reported rates between 41% and 70%. Interestingly, age was not a significant predictor of Demodex blepharitis in this study, suggesting that it can affect patients of all ages. Furthermore, collarettes, a sign of Demodex blepharitis, were frequently overlooked in patients who hadn't been previously diagnosed with blepharitis, indicating substantial underdiagnosis.

The study also highlighted a significant overlap between Demodex blepharitis and dry eye disease (DED), with nearly 60% of DED patients also having Demodex blepharitis. This suggests that Demodex infestation may contribute to or exacerbate DED. Surprisingly, the use of certain topical medications for DED, like lifitegrast and cyclosporine, did not seem to mitigate Demodex blepharitis, emphasizing the need for effective treatments targeting this condition to improve outcomes for DED patients.

Researchers discovered that Demodex blepharitis' prevalence was similar to that of DED (58.4%; n=593/1015), indicating that Demodex blepharitis is nearly as common as DED. Nearly 60% of patients had both DED and Demodex blepharitis, highlighting the overlap of these diseases. Researchers suggest that Demodex blepharitis may play a role in the contribution to or exacerbation of DED.

"Treatment for ocular surface disease may be unsuccessful and frustrate both patients and clinicians if a major underlying cause, Demodex mite infestation, is not addressed," said researchers.

Researchers also noted, in the present study, nearly two-thirds of glaucoma patients from the dataset also had Demodex blepharitis. Researchers suggest, "the high prevalence of Demodex blepharitis seen in glaucoma patients in this study suggests that glaucoma patients should be screened for Demodex infestation to ensure that the disease is treated in a timely fashion so as to avoid contributing to ocular symptoms that affect medication compliance."

Although this study demonstrates the high prevalence of Demodex blepharitis, researchers claim that clinicians do not conduct routine screening for it, even if the patients complain about its symptoms. Researchers believe this can be due to "a lack FDA-approved prescription therapeutics, poor standardization and inconsistent levels of success with various over-the-counter management options, the potential toxicity of TTO to meibomian epithelial cells, and/or the discomfort and side effects."

Reference

Trattler W, Karpecki P, Rapoport Y, et al. The prevalence of Demodex blepharitis in US eye care clinic patients as determined by collarettes: a pathognomonic sign. Clinical Ophthalmology. 2022;Volume 16:1153-1164. doi:10.2147/opth.s354692