Blepharitis

Classification

Anterior Blepharitis

Posterior Blepharitis (Meibomian Gland Dysfunction - MGD)

• Caused by dysfunction of the meibomian glands within the tarsal plate
• Bacterial lipases generate free fatty acids from meibum, raising its melting point and causing inspissation (plugging) of gland orifices
• Results in unstable tear film, increased evaporation, and ocular surface irritation
• Strongly associated with acne rosacea

Aetiology and Pathophysiology

• Staphylococcus aureus is the most common infectious agent overall
• An abnormal cell-mediated immune response to S. aureus cell wall components may cause the peripheral corneal infiltrates seen in some patients
• Demodex mites (D. folliculorum longus in anterior; D. folliculorum brevis in posterior) play a causative role in many chronic cases
  • Collarettes (cylindrical sleeves of keratin/mite eggs at lash bases) are considered pathognomonic of Demodex infestation
  • Microscopic examination of an epilated lash confirms the diagnosis

Symptoms

• Burning, grittiness, itching, foreign body sensation
• Mild photophobia
• Crusting around the eyes worse in the mornings (in contrast to dry eye, which worsens later in the day)
• Tearing, mild mucous discharge
• Contact lens intolerance
• Remissions and exacerbations are typical

Signs

Critical Signs

• Crusty, red, thickened eyelid margins with prominent blood vessels
• Inspissated (plugged) meibomian gland orifices
• Collarettes or cylindrical sleeves around lashes
• Scales at lash bases (hard in staphylococcal; soft/greasy in seborrhoeic)

Other Signs

• Conjunctival injection, papillary conjunctivitis
• Superficial punctate keratopathy (SPK)
• Corneal infiltrates, marginal keratitis, phlyctenules
• Corneal vascularization/pannus (in severe or chronic disease)
• Foaming at lid margins (posterior/MGD)
• Hordeolum (stye) or chalazion formation
• Lash loss (madarosis), misdirected lashes (trichiasis)

Complications / Secondary Changes

• Blepharoconjunctivitis (conjunctival and corneal co-inflammation)
• Salzmann nodular degeneration
• Bacterial keratitis (especially in contact lens wearers)
• Phlyctenular eye disease
• Dry eye syndrome (unstable tear film)

Differential Diagnosis

• Pediculosis (Phthirus pubis infestation of lashes)
• Demodicosis (look specifically for cylindrical sleeves)
• Ocular rosacea (telangiectasias of lid margin, facial flushing)
• Sebaceous carcinoma - important: intractable, unilateral, or asymmetric blepharitis (upper vs. lower lid asymmetry) should raise suspicion and warrants workup

Treatment

1. Lid Hygiene (First-line for all forms)

• Apply warm compresses for 5-10 minutes b.i.d. to q.i.d. to soften crusts and melt inspissated meibum
• Follow with lid margin scrubbing using a clean wet cloth or commercial eyelid scrub pads
  • Note: Baby shampoo is NOT recommended by Kanski; it destabilizes the tear film and can cause contact dermatitis
• For significant MGD: manually express meibomian glands by rolling a finger over the lid margin

2. Dry Eye / Tear Support

• Preservative-free artificial tears 4-8 times/day if associated dry eye is present

3. Topical Antibiotics (Moderate-severe anterior disease)

• Erythromycin ointment, azithromycin gel-drop, sodium fusidic acid, bacitracin, or chloramphenicol applied to the lid margin at bedtime (q.h.s.)

4. Oral Antibiotics (Significant posterior/MGD or refractory cases)

• Doxycycline: 50-100 mg twice daily for 1 week, then daily for 6-24 weeks
• Lymecycline: 408 mg daily for up to 3 months
• Azithromycin: 500 mg/day x 3 days for 3 cycles at 1-week intervals
• Tetracyclines reduce bacterial colonization and inhibit staphylococcal lipase production
• Contraindicated in pregnancy, breastfeeding, and children ≤8 years - use erythromycin 200 mg b.i.d. in these groups

5. Anti-inflammatory / Immunomodulatory Agents

• Cyclosporine 0.05% or 0.09% eye drops b.i.d.
• Lifitegrast 5% drops b.i.d.
• Low-dose topical steroids (prednisolone 0.1% or fluorometholone 0.1%) for phlyctenular disease or corneal infiltrates
• Omega-3 fatty acid oral supplementation

6. Demodex-specific Treatment

• Suspected when collarettes are present and standard treatment has failed
• Tea tree oil eyelid scrubs or eyelid cleansing agent with hypochlorous acid once or twice daily for minimum 6 weeks

7. Advanced/Interventional (Refractory MGD)

• Thermal treatment with meibomian gland expression
• Intense pulsed light (IPL) laser therapy
• Microblepharoexfoliation
• Probing of meibomian glands

Special Variants

Angular Blepharitis

• Erythema, scaling, maceration, and fissuring at the lateral and/or medial canthi
• Caused by Moraxella lacunata or S. aureus
• Treatment: topical chloramphenicol, bacitracin, or erythromycin

Childhood Blepharokeratoconjunctivitis (BKC)

• More severe in Asian and Middle Eastern children; onset around age 6
• Presents with recurrent anterior/posterior blepharitis, styes, chalazia, eye rubbing, photophobia
• May be mistaken for allergic eye disease
• Treatment: lid hygiene + topical antibiotic ointment; erythromycin syrup 125 mg/day for 4-6 weeks for systemic coverage; low-dose topical steroids as needed

Follow-Up

• Review at 2-4 weeks depending on severity
• Lid scrubs and warm compresses can be reduced to once daily as symptoms improve, but often must be maintained indefinitely to prevent relapse
• Advise patients that the condition is chronic and a permanent cure is unlikely