Etiology of Blepharitis
WESTERN OPHTHALMIC HOSPITAL/SCIENCE PHOTO LIBRARY
Blepharitis may be acute (ulcerative or nonulcerative) or chronic (caused by meibomian gland dysfunction, seborrheic blepharitis, Demodex infestation).
Acute blepharitis
Acute ulcerative blepharitis is usually caused by bacterial infection (usually staphylococcal) of the eyelid margin at the origins of the eyelashes; the lash follicles and the meibomian glands are also involved. It may also be due to a virus (eg, herpes simplex, varicella zoster). Bacterial infections typically have more crusting than the viral type, which usually has more of a clear serous discharge.
Acute nonulcerative blepharitis is usually caused by an allergic reaction involving the same area (eg, atopic blepharodermatitis and seasonal allergic blepharoconjunctivitis), and causes the following:
Intense itching and inflammation (usually along the edges of both eyelids);
Rubbing (a response to itching that can increase conjunctival itching and exacerbate atopic dermatitis [eczema] of the eyelid); or
Contact sensitivity (dermatoblepharoconjunctivitis).
Chronic blepharitis
Chronic blepharitis is noninfectious inflammation of unknown cause. Meibomian glands in the eyelid produce lipids (meibum) that reduce tear evaporation by forming a lipid layer on top of the aqueous tear layer. In meibomian gland dysfunction, the lipid composition is abnormal, and gland ducts and orifices become inspissated with hard, waxy plugs. Many patients have rosacea and recurrent hordeola or chalazia.
Many patients with seborrheic blepharitis have seborrheic dermatitis of the face and scalp or acne rosacea. Secondary bacterial colonization often occurs on the scales that develop on the eyelid margin. Meibomian glands can become obstructed.
DR P. MARAZZI/SCIENCE PHOTO LIBRARY
Most patients with meibomian gland dysfunction or seborrheic blepharitis have increased tear evaporation and secondary keratoconjunctivitis sicca, also known as dry eye. Demodex (folliculorum and brevis species) infestation is also a common cause of chronic blepharitis.
Chronic blepharitis can also occur in patients with eyelid carcinoma (especially if blepharitis is unilateral and there is loss of eyelashes) or immune-mediated conditions such as ocular mucous membrane pemphigoid.
Symptoms and Signs of Blepharitis
Symptoms common to all forms of blepharitis include itching and burning of the eyelid margins and conjunctival irritation with lacrimation, photosensitivity, and foreign body sensation. Itching is more common in allergic than infectious causes. Symptoms tend to be worse in the early morning than those of keratoconjunctivitis sicca, which tend to be worse toward the end of the day.
Acute blepharitis
In acute ulcerative blepharitis, small pustules may develop in eyelash follicles and eventually break down to form shallow marginal ulcers. Tenacious adherent crusts leave a bleeding surface when removed. During sleep, eyelids can become glued together by dried secretions. Recurrent ulcerative blepharitis can cause eyelid scars and loss or misdirection (trichiasis) of eyelashes.
In acute nonulcerative blepharitis, eyelid margins become edematous and erythematous; eyelashes may become crusted with dried serous fluid.
Chronic blepharitis
In meibomian gland dysfunction, examination reveals dilated, inspissated gland orifices that, when pressed, exude a waxy, thick, yellowish secretion. In seborrheic blepharitis, greasy, easily removable scales develop on eyelid margins. Most patients with seborrheic blepharitis and meibomian gland dysfunction have symptoms of keratoconjunctivitis sicca, such as foreign body sensation, grittiness, eye strain and fatigue, and blurring with prolonged visual effort. In Demodex infestation, patients may have chronic blepharitis that has not responded to standard treatments; symptoms include redness, inflammation, itching, and recurrent styes. Examination in Demodex infestation reveals cylindrical sleeves on the eyelashes, usually at the base.
Diagnosis of Blepharitis
Slit-lamp examination
Diagnosis is usually by slit-lamp examination. Chronic blepharitis that does not respond to treatment may require biopsy to exclude eyelid tumors or immune-mediated conditions that can simulate the condition.
Treatment of Blepharitis
Antimicrobials for acute ulcerative blepharitis; warm compresses and sometimes topical corticosteroids for acute nonulcerative blepharitis
For chronic blepharitis, treatment of keratoconjunctivitis sicca, warm compresses, cleansing of eyelids, and sometimes topical or systemic antibiotics as clinically indicated
Demodex infestation
Acute blepharitis
Treatment of acute nonulcerative blepharitis begins with avoiding the offending action (eg, rubbing) or substance (eg, new eye drops). Warm compresses over the closed eyelid may relieve symptoms and speed resolution. If swelling persists >
Chronic blepharitis
The initial treatment for both meibomian gland dysfunction and seborrheic blepharitis is directed toward eyelid hygiene and warm compresses, which melt the waxy plugs. Occasionally, eyelid massage is needed to extrude trapped secretions and coat the ocular surface.
Blepharitis associated with Demodex infestation should be initially treated with topical low-concentration tea tree oil or hypochlorous acid. If the condition is unresponsive to these over-the-counter remedies, an ectoparasiticide can be prescribed (1).
Secondary keratoconjunctivitis sicca may also develop when dysfunctional meibomian glands produce a poor oil layer, resulting in increased tear evaporation. Tear supplements during the day, bland ointments (eg, petroleum jelly) at night and, if necessary, punctal plugs (inserts that obstruct the puncta and thus decrease tear drainage) are effective in most patients.
Treatment reference
1. Amescua G, Akpek EK, Farid M, et al: Blepharitis Preferred Practice Pattern®. Ophthalmology 126(1):P56-P93. doi: 10.1016/j.ophtha.2018.10.019
Prognosis for Blepharitis
Acute blepharitis most often responds to treatment but may recur, develop into chronic blepharitis, or both. Chronic blepharitis is indolent, recurrent, and resistant to treatment. Exacerbations are inconvenient, uncomfortable, and cosmetically unappealing but do not usually result in corneal scarring or vision loss. Long-term maintenance and preventive care with warm compresses and eyelid hygiene is critical.
Key Points
Common forms of blepharitis include acute ulcerative (often secondary to staphylococcal or herpes virus infection), acute nonulcerative (usually allergic), and chronic (often with meibomian gland dysfunction, seborrheic dermatitis, or Demodex infestation).
Secondary keratoconjunctivitis sicca usually accompanies chronic blepharitis.
Common symptoms include itching and burning of the eyelid margins and conjunctival irritation with lacrimation, photosensitivity, and foreign body sensation.
Diagnosis is usually by slit-lamp examination.
Consider alternate diagnoses, including eyelid carcinoma, if chronic blepharitis is unilateral.
Supportive treatments are indicated (eg, warm compresses, eyelid cleansing, and treatment of keratoconjunctivitis sicca as needed).
Specific medication treatments can include topical antimicrobials for acute ulcerative blepharitis, systemic antivirals if viral infection is suspected, and topical corticosteroids for persistent acute nonulcerative blepharitis.
Treatment of chronic blepharitis includes treatment of keratoconjunctivitis sicca with tear supplements, use of warm compresses and, topical or systemic antibiotics as needed.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Michelle K. Rhee, Elizabeth Yeu, Melissa Barnett, et al: Demodex blepharitis: A comprehensive review of the disease, current management, and emerging therapies. Eye & Contact Lens: Science & Clinical Practice. 49(8):311-318. DOI: 10.1097/ICL.0000000000001003OPEN
