Scleritis

Symptoms

• severe, boring eye pain: often radiates to the forehead, jaw, or sinuses
• nocturnal awakening: the pain is classically severe enough to wake the patient from sleep
• pain with movement: discomfort worsens with eye movement and palpation of the globe
• gradual or acute redness: the eye often develops a deep, violaceous (purple) hue
• tearing and photophobia: common associated symptoms; vision may also be decreased

Clinical Findings

Anterior segment

• deep scleral injection: large, deep vessels that do NOT blanch with 10% phenylephrine
• violaceous hue: a characteristic purple color seen best under natural sunlight
• scleral edema: may be diffuse, sectoral, or manifest as a localized nodule
• immobility: unlike episcleral vessels, scleral vessels cannot be moved with a cotton swab

Necrotizing features

• scleral thinning: the underlying dark uvea becomes visible through the translucent sclera
• avascular patches: areas where the superficial and deep vascular plexuses are missing

Posterior scleritis

• t-sign on b-scan: fluid in Tenon’s space and optic nerve sheath thickening
• fundus signs: choroidal folds, disc edema, or an exudative retinal detachment

Etiology

Systemic associations (~50%)

• rheumatoid arthritis (ra): the most common underlying systemic cause
• gpa (wegener granulomatosis): often associated with more severe, necrotizing forms
• relapsing polychondritis: look for inflamed cartilage (ears or nose)
• inflammatory bowel disease (ibd) and systemic lupus erythematosus (sle)

Infectious & traumatic

• infectious: herpes zoster, syphilis, tuberculosis, or pseudomonas (post-surgery)
• surgical: history of pterygium surgery with Mitomycin-C or scleral buckle

Red Flags

• necrotizing scleritis: a medical emergency with high mortality if systemic vasculitis is present
• scleromalacia perforans: painless scleral melting; classic in long-standing RA
• posterior scleritis: can mimic a choroidal tumor; check for the "T-sign" on B-scan
• phenylephrine failure: if the redness persists after drops, it is scleritis, not episcleritis

Investigations

The phenylephrine test

• apply 2.5% or 10% phenylephrine; episcleritis blanches, scleritis does not

Imaging

• b-scan ultrasound: mandatory if posterior scleritis is suspected (look for T-sign)

Systemic workup (rheumatology panel)

• labs: cbc, esr, crp, rf, anti-ccp, ana, anca (c-ANCA/p-ANCA), ace
• infectious: rpr/fta-abs (syphilis), quantiferon-tb gold, chest x-ray

Treatment

Non-necrotizing

• oral nsaids: indomethacin 50 mg tid (with a ppi for stomach protection)
• oral steroids: prednisone (60–80 mg) if nsaids fail or if disease is bilateral

Necrotizing or refractory

• aggressive immunosuppression: methotrexate, mycophenolate, or biologics (anti-tnfα)
• iv steroids: pulse methylprednisolone for sight-threatening or severe pain

Contraindications

• avoid subconjunctival steroid injections in necrotizing cases (risk of perforation)

Clinical Pearl

Scleritis is associated with systemic disease in 50% — most commonly rheumatoid arthritis (the most common association), GPA (Wegener granulomatosis), relapsing polychondritis, IBD. Necrotizing scleritis without inflammation (scleromalacia perforans) occurs in long-standing RA with high mortality. Always phenylephrine test: blanches episcleritis (superficial), not scleritis.

Differential Diagnosis

• • episcleritis (blanches with phenylephrine, minimal pain, no bluish hue)
• • conjunctivitis (discharge present, itching, superficial vessels)
• • orbital cellulitis (proptosis, fever, limited motility)

Related Sclera Conditions

• Episcleritis