Scleritis

BASICS

Definition: Painful, inflammatory process of the sclera (outer coat of the eye), potentially vision-threatening.
Types: Anterior (94%—diffuse, nodular, necrotizing) or posterior (6%); necrotizing forms are most severe.
Contrast: Episcleritis is self-limited, mild, and involves the superficial episclera.
System Affected: Ocular.

Mean age: 54 years (range 12–96)
Sex: Female > male (1.6:1)
Incidence: 6 per 100,000
Prevalence: Most cases are anterior scleritis, with diffuse type most common.

Systemic Association: Frequently associated with systemic autoimmune disease (esp. rheumatoid arthritis).
Other Causes: Bisphosphonate drugs, surgical trauma (esp. necrotizing), infection (post-surgery, Pseudomonas in diabetics).
Pathogenesis: Varies by type—matrix metalloproteinases involved in necrotizing scleritis.

Autoimmune disorders (esp. rheumatoid arthritis, Sjögren, granulomatosis with polyangiitis, SLE, Behçet)
Infectious disease, drug exposure (bisphosphonates), multiple ocular surgeries

Rheumatoid arthritis (most common)
Sjögren syndrome, granulomatosis with polyangiitis, HLA-B27 spondyloarthropathies, SLE, Behçet, juvenile idiopathic arthritis, Cogan disease, relapsing polychondritis, polyarteritis nodosa, sarcoidosis, IBD
Herpes zoster/simplex, HIV, syphilis, Lyme disease, TB

Symptoms: Scleral redness and inflammation; bilateral in ~40%
Pain: Deep, constant, severe, may radiate to eyebrow, temple, jaw, awaken patient at night (worst in necrotizing)
Other: Photophobia, tearing

Inspect sclera in all gaze directions; bluish hue = thinning
Assess for injection, thinning, nodules, vision changes
Visual Acuity: ↓ in ~16% (≥2 Snellen lines)
Slit-lamp Exam: Deep vascular congestion, blue/violet hue (scleritis), blanches poorly with phenylephrine
Differentiate: Episcleritis = superficial, blanches, mild; Scleritis = deeper, more severe

Episcleritis, conjunctivitis, iritis, posterior uveitis, blepharitis, ocular rosacea

Labs: CBC, chemistry, ESR, CRP, RF, anti-CCP, ANA, ACE, HLA-B27, ANCA, PPD/QuantiFERON-TB, RPR, FTA-ABS, Lyme titers, urinalysis, blood/urine cultures
Imaging: Chest X-ray, sacroiliac films, colonoscopy (if indicated)
Ocular Imaging: B-scan US (for posterior scleritis, T-sign), MRI/CT (if orbital disease)
Biopsy: Rarely required (if diagnosis unclear or infection suspected)
Subtypes:
- Diffuse anterior: widespread inflammation
- Nodular anterior: immobile nodule
- Necrotizing anterior: transparent sclera, scleromalacia perforans (painless, RA)
- Posterior: may cause retinal/choroidal complications, orbital swelling

NSAIDs: Ibuprofen 600–800 mg PO TID-QID, indomethacin 50 mg PO TID (if no contraindications; ~37% respond)
Systemic Steroids: Prednisone 40–60 mg PO QD (or 1 mg/kg/day), taper over 4–6 weeks. IV steroids for necrotizing or vision threat.
Steroid-sparing Agents: Methotrexate, azathioprine, mycophenolate, cyclophosphamide, cyclosporine (for chronic or steroid-dependent/refractory cases)
Immunomodulators: Infliximab, rituximab, adalimumab (for refractory cases—prefer over etanercept)

Topical Steroids: Prednisolone acetate 1%, difluprednate 0.05% (ophthalmologist only)
Subconjunctival Steroid Injection: Triamcinolone acetonide for non-necrotizing scleritis
Infectious Etiology: Antibiotics and surgical intervention if needed

Chronic, often progressive; recurrent flares possible
Best: Diffuse anterior scleritis; Worst: Necrotizing (risk of globe perforation, vision loss)
Scleromalacia perforans = highest perforation risk

Scleritis is severe, painful, and can threaten vision—unlike mild, self-limited episcleritis.
~35% associated with systemic disease (most commonly RA); necrotizing scleritis = highest association.
Early recognition and systemic workup are critical to prevent vision loss and address underlying disease.