Episcleritis
Definition
Inflammation of the episcleral tissue between the conjunctiva and sclera, typically presenting as a sectoral or diffuse area of injection that blanches with topical phenylephrine, usually self-limiting and mildly symptomatic.
Clinical Snapshot
Episcleritis is a benign, self-limiting inflammation of the episcleral tissue — the loose connective tissue between the conjunctiva and the sclera. It presents as a sectoral (simple episcleritis) or diffuse area of injection that blanches with topical 2.5% phenylephrine, distinguishing it from the deeper, non-blanching injection of scleritis. Symptoms are typically mild — discomfort rather than the severe boring pain of scleritis. Most cases resolve spontaneously within 2–3 weeks. Systemic disease association is present in approximately 30% of cases but is less common and less serious than in scleritis.
Epidemiology
Episcleritis is common — it is one of the most frequent causes of acute red eye in young adults. It predominantly affects women in the third to fifth decades. Simple (sectoral) episcleritis is more common than nodular episcleritis.
Pathophysiology
Episcleritis results from inflammation of the episcleral vascular plexus. The episcleral vessels are superficial and blanch with topical vasoconstrictors (phenylephrine), distinguishing them from the deeper scleral vessels of scleritis. The etiology is often idiopathic; systemic associations include inflammatory bowel disease, rheumatoid arthritis, gout, and atopy.
Risk Factors
- Inflammatory bowel disease (Crohn's, ulcerative colitis)
- Rheumatoid arthritis
- Gout (uric acid crystal deposition)
- Atopy
- Rosacea
- Idiopathic (the majority)
Clinical Presentation
Acute onset of unilateral (occasionally bilateral) sectoral or diffuse conjunctival and episcleral injection. Mild discomfort or foreign body sensation — not the severe boring pain of scleritis. Watery discharge. The injection blanches with topical 2.5% phenylephrine — the key distinguishing feature from scleritis. Nodular episcleritis: a raised, tender episcleral nodule that moves freely over the underlying sclera.
Diagnostic Pearls
- The phenylephrine blanching test is the key clinical maneuver — instill 2.5% phenylephrine; blanching of the injection within 10–15 minutes confirms episcleritis rather than scleritis.
- Scleral translucency is preserved in episcleritis — scleral thinning or a bluish hue suggests scleritis.
- Nodular episcleritis is more likely to be associated with systemic disease than simple episcleritis.
- Pain severity is the most important clinical differentiator — episcleritis causes discomfort; scleritis causes severe, boring pain that may wake the patient from sleep.
Differential Diagnosis
- Scleritis (severe boring pain, non-blanching, scleral edema)
- Bacterial conjunctivitis (purulent discharge, diffuse injection)
- Allergic conjunctivitis (itching, chemosis)
- Pingueculitis (localized injection around a pinguecula)
Evidence-Based Management
Most cases of simple episcleritis resolve spontaneously within 2–3 weeks without treatment. Symptomatic relief: topical NSAIDs (ketorolac), cold compresses, and lubricating drops. Topical corticosteroids (low-potency: FML®, loteprednol) may hasten resolution but are generally not required. Oral NSAIDs (ibuprofen, indomethacin) for nodular or recurrent episcleritis. Systemic disease evaluation for recurrent or bilateral cases.
Monitoring & Follow-Up
Follow up in 2–3 weeks to confirm resolution. Recurrent episcleritis warrants systemic evaluation for associated conditions.
Clinical Pearls
- Episcleritis is benign and self-limiting — reassurance is an important component of management.
- The phenylephrine blanching test is the most important clinical maneuver — it distinguishes episcleritis from the potentially sight-threatening scleritis.
- Recurrent episcleritis warrants systemic evaluation — inflammatory bowel disease and rheumatoid arthritis are the most common associations.
- Topical corticosteroids are generally not required for simple episcleritis — they carry risks (IOP elevation, cataract) that outweigh the benefit for a self-limiting condition.
Related Therapeutics — Clinician's Companion
- Anti-inflammatory Rescue — FML®, Lotemax® (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.