Pick up any optometry journal from the past year and you’re likely to encounter an article related to Demodex or lid margin disease. It’s relevant dialog, considering the frequency in which we treat blepharitis. But, at times, uncovering the science and deciphering the research can be daunting.

We tend to put all cases of blepharitis into one category and treat it using essentially the same protocol, which could explain why some patients don’t respond properly.  
Patients typically present with debris and collarettes on the lashes, and frequently report itching, flaking, crusting and matting of the lashes in the morning.^₁

The condition also may yield symptoms of burning, irritation, tearing and red eyes.^_2-3 Although mild in presentation, blepharitis can progress and predispose the patient to more serious issues, such as permanent eyelid margin alteration, or vision loss secondary to phylectenules, marginal keratitis, corneal neovascularization, ulceration, punctate erosions or superficial punctate keratopathy.^_4-6 Low-grade bacterial infections may contribute to the pathogenesis, although the exact mechanism is unknown. Other causes include overgrowth or infestation by parasites and dermatological conditions ranging from seborrhea to eczema.^₇

Blepharitis is often categorized as chronic or acute, anterior or posterior (as is the case with meibomian gland dysfunction), and its etiology is typed as Staphylococcal, Demodex or seborrheic.
Staphylococcal Blepharitis

This form, in which patients typically complain of matting, debris and redness or irritation of the eyelids, is the most common observed in clinical practice.^₈ Interestingly, research shows a significant increase in the number of blepharoconjunctivitis cases caused by methicillin-resistant Staphylococcus aureus (MRSA). MRSA was responsible for 4.1% of all cases reported from 1998 to 1999, but 16.7% in 2005 to 2006.^₉ The increase appears to be the result of antibiotic resistance.
Of all possible ocular infections caused by MRSA, 78% were blepharoconjunctivitis vs. 22% for all other conditions, including keratitis or endophthalmitis.^₉ Topical medications such as besifloxacin and polymyxin B/trimethoprim, which are known to be effective against MRSA, are likely the best treatment options.^_10-12

Chronic blepharitis typically evolves into inflammatory eye disease, and is best treated with an antibiotic/corticosteroid combination agent or corticosteroids alone.5,13  More severe cases may warrant the use of oral medications, such as doxycycline (50mg BID for one to two months) for adults or erythromycin (dose based on weight, for one to two weeks) for children.14-16

Remember, most patients with anterior Staphylococcal blepharitis have concurrent meibomian gland dysfunction. Warm compress masks or meibomian gland treatments may be needed as well.

Lid hygiene is also critical. Although patients have long been instructed to use baby shampoo to cleanse the affected area, compliance is greater with commercial products––particularly foam cleansers that can be applied in the shower each day.

Demodex Blepharitis
Demodex are intradermal parasites that thrive in follicles and sebaceous glands.^₁₇ Research suggests that altered fatty acid profiles produce sebum that encourage mite development.^₁₈ In addition to ocular inflammation, chalazion development, lid margin irritation and even corneal involvement, Demodex is a known risk factor for pterygium recurrence.^₁₉

Demodex infestation is the most common cause of non-responsive or persistent blepharitis, and is often associated with ocular surface inflammation in elderly patients or those with rosacea.^_20-21 It can also be found in immunocompromised individuals secondary to medication use or HIV.^₂₂

Patients with Demodex blepharitis typically complain of itching, irritation and thinning or loss of lashes. The appearance is that of a “sleeve” at the base of the lashes.

Proposed treatments include the oral antiparasitic agent ivermectin, but the condition may be treated more effectively with commercial products that contain 4-terpineol, the active ingredient of tea tree oil.^_23-24

Seborrheic Blepharitis
Patients with seborrheic blepharitis typically complain of eyelash flaking and eyelid redness or irritation. Some research suggests that Malassezia, a species of fungi commonly found on the skin, may be the culprit.^₂₄

Because seborrheic blepharitis is more of a dermatological condition, it presents similarly to other common skin conditions like eczema. Scaly eyelids and flaky debris are typical.^₂₅ Additionally, patients with atopic keratoconjunctivitis often experience periorbital ezcema.

An effective treatment for these forms of blepharitis may involve a steroid preparation, such as topical triamcinolone cream; limit use to two or three weeks on the eyelids. Consider topical loteprednol ointment and eyelid cleansing pads if there’s a risk of the medication getting into the eyes. If non-responsive, consider oral antifungal medications.^₂₆

Rather than approach each case of blepharitis with a similar treatment regimen, learn to differentiate its many forms. This will ensure proper diagnosis and more effective treatment.

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2. Bernardes TF, Bonfioli AA. Blepharitis. Semin Ophthalmol. 2010 May;25(3):79-83.
3. Wong VW, Lai TY, Chi SC, et al. Pediatric ocular surface infections: a 5-year review. Cornea. 2011 Sep;30(9):995-1002.
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14. Doherty JM, McCulley JP, Silvany RE, et al. The role of tetracycline in chronic blepharitis. Invest Ophthal Vis Sci 1991;32:2970-5.
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17. Kulac M, Ciftci IH, Karaca S, et al. Clinical importance of D folliculorum in patients receiving phototherapy. Int J Dermatol. 2008 Jan;47(1):72-7.
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20. Liu J, Sheha H, Tseng SC. Pathogenic role of Demodex mites in blepharitis. Curr Opin Allergy Clin Immunol. 2010 Oct;10(5):505-10.
21. Li J, O’Reilly N, Sheha H, et al. Correlation between Demodex Infestation and Serum. Immunoreactivity to Bacillus proteins in patients with facial rosacea. Ophthalmology. 2010 May;117(5):870-7.
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23. Tighe S, Ying-Ying G, Tseng CG. Terpinen-4-ol most active ingredient of tea tree oil to kill demodex. Transl Vis Sci Technol. 2013 Nov;2(7):2.
24. Zisoya LG. Treatment of Malassezia species associated seborrheic blepharitis with fluconazole. Folia Med (Plovdiv). 2009 Jul-Sep;51(3):57-9.
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