Scleritis
Definition
Inflammation of the sclera, classified as anterior (diffuse, nodular, or necrotizing) or posterior, characterized by severe deep boring pain, scleral edema, and violaceous discoloration that does not blanch with phenylephrine.
Clinical Snapshot
Scleritis is a serious, potentially sight-threatening inflammation of the sclera. It is classified as anterior (diffuse, nodular, or necrotizing — with or without inflammation) or posterior. The hallmarks are severe, deep boring pain (often nocturnal, radiating to the face and jaw), scleral edema, and violaceous discoloration that does not blanch with topical phenylephrine. Systemic disease is associated in approximately 50% of cases — rheumatoid arthritis and granulomatosis with polyangiitis (GPA) are the most common. Necrotizing scleritis carries the highest risk of vision loss and scleral perforation.
Epidemiology
Scleritis has an annual incidence of approximately 6 per 100,000. It predominantly affects women (60–70%) in the fourth to sixth decades. Systemic disease is associated in approximately 50% of cases — rheumatoid arthritis is the most common association (approximately 30%).
Pathophysiology
Scleritis results from immune complex deposition and T-cell–mediated inflammation in the scleral stroma. The scleral vessels are deep and do not blanch with topical vasoconstrictors. Necrotizing scleritis involves vasculitis of the scleral vessels, leading to ischemia, scleral thinning, and risk of perforation. Posterior scleritis involves the posterior sclera and can cause exudative retinal detachment, choroidal folds, and optic disc edema.
Risk Factors
- Rheumatoid arthritis (the most common systemic association)
- Granulomatosis with polyangiitis (GPA — formerly Wegener's)
- Systemic lupus erythematosus
- Relapsing polychondritis
- Inflammatory bowel disease
- Gout
- Herpes zoster (infectious scleritis)
Clinical Presentation
Severe, deep boring pain — often nocturnal, radiating to the periorbital area, temple, and jaw. Scleral edema and violaceous (bluish-red) discoloration. The injection does not blanch with topical 2.5% phenylephrine. Diffuse anterior scleritis: widespread scleral involvement. Nodular anterior scleritis: raised, tender scleral nodule that does not move freely (unlike episcleral nodule). Necrotizing scleritis: scleral thinning, avascular areas, and risk of perforation. Posterior scleritis: pain, proptosis, restricted motility, choroidal folds, exudative retinal detachment — may mimic orbital cellulitis or choroidal tumor.
Diagnostic Pearls
- The phenylephrine blanching test is the key clinical maneuver — non-blanching injection confirms scleritis over episcleritis.
- Posterior scleritis is frequently misdiagnosed — B-scan ultrasonography showing the "T-sign" (fluid in Tenon's space) is pathognomonic.
- Systemic workup is mandatory: CBC, ESR, CRP, RF, ANA, ANCA, uric acid, chest X-ray, and syphilis serology.
- Necrotizing scleritis without inflammation (scleromalacia perforans) is associated with long-standing rheumatoid arthritis — it is painless but carries a high risk of perforation.
Differential Diagnosis
- Episcleritis (blanches with phenylephrine, mild discomfort)
- Orbital cellulitis (fever, proptosis, restricted motility)
- Choroidal melanoma (posterior scleritis mimics)
- Thyroid eye disease (bilateral, no pain)
Evidence-Based Management
Oral NSAIDs (indomethacin 25–50 mg TID, ibuprofen 400–600 mg TID) are first-line for non-necrotizing anterior scleritis. Oral corticosteroids (prednisone 1 mg/kg/day) for NSAID-refractory or necrotizing disease. Immunosuppressive agents (methotrexate, mycophenolate, cyclophosphamide for GPA-associated necrotizing scleritis) for steroid-sparing or refractory disease. Biologics (rituximab for GPA-associated scleritis) for refractory cases. Topical corticosteroids have limited utility for scleritis — the inflammation is too deep. Systemic disease management in collaboration with rheumatology.
Monitoring & Follow-Up
Weekly follow-up during active disease. Monitor scleral thickness and vascularity. Systemic co-management with rheumatology is essential for disease-associated scleritis.
Clinical Pearls
- Scleritis is a systemic disease marker — always perform a systemic workup, even for a first episode.
- Necrotizing scleritis is the most dangerous form — it requires aggressive systemic immunosuppression and close monitoring for scleral perforation.
- Posterior scleritis is frequently misdiagnosed — B-scan ultrasonography with the T-sign is the key diagnostic test.
- Topical corticosteroids are ineffective for scleritis — the inflammation is in the scleral stroma, beyond the reach of topical agents.
Related Therapeutics — Clinician's Companion
- Oral Therapeutics — Oral Prednisone, Methotrexate (Clinician's Companion)
Key References
- 1.Watson PG, Hayreh SS. Scleritis and episcleritis. Br J Ophthalmol. 1976.
- 2.Jabs DA, et al. Episcleritis and scleritis: clinical features and treatment results. Am J Ophthalmol. 2000.
This entry is an educational reference designed to support clinical reasoning and awareness. It does not constitute medical advice, establish a standard of care, or replace individualized patient assessment. Clinicians should consult current guidelines and applicable clinical resources when making patient care decisions.