Episcleritis

Episcleritis: Superficial Scare

• Definition: Inflammation of the episclera, a thin, vascularized connective tissue layer.
• Anatomy:
  • Episclera: Lies between the superficial conjunctiva and the deeper sclera.
  • Tenon's Capsule (fascia bulbi): Ensheathes the globe, situated external to the episclera.
  • Conjunctiva: Outermost mucous membrane.

⭐ Episcleritis is an inflammation of the episclera, the tissue between the conjunctiva and sclera; it's typically benign and self-limiting. Vessels blanch with topical phenylephrine 2.5%.

Episcleritis Etiology: The Why & Who

• Idiopathic: Most frequent; specific cause often unidentified.

  ⭐ Approximately 66% (two-thirds) of episcleritis cases are idiopathic.

• Systemic Associations (up to 1/3rd of cases):
  • Connective Tissue Diseases:
    • Rheumatoid Arthritis (RA) - most common systemic link
    • Systemic Lupus Erythematosus (SLE)
    • Inflammatory Bowel Disease (IBD) (Crohn's, Ulcerative Colitis)
  • Vasculitides:
    • Granulomatosis with Polyangiitis (GPA)
    • Polyarteritis Nodosa (PAN)
  • Metabolic:
    • Gout
• Infections (Less Common):
  • Herpes Zoster Virus (HZV)
  • Lyme Disease
  • Syphilis

Episcleritis Features: Red Alert Signs

• Symptoms:

  • Acute onset, often unilateral (can be bilateral).
  • Redness: Sectoral (most common) or diffuse.
  • Discomfort: Mild, grittiness, foreign body sensation, watering.
  • Pain: Typically mild, aching, or absent; NOT severe, boring pain.
  • Vision: Usually normal.
  • Photophobia: Mild or absent.

• Signs:

  • Bright red vascular congestion (episcleral vessels).
  • Vessels blanch with topical phenylephrine 2.5% or 10%.

    ⭐ Episcleral vessels blanch with topical phenylephrine, a key diagnostic sign distinguishing it from scleritis.

• Types:

  Feature	Simple Episcleritis	Nodular Episcleritis
  Appearance	Diffuse or sectoral redness	Localized, raised, mobile nodule
  Commonality	Most common	Less common
  Resolution	Resolves faster (days to weeks)	May take longer to resolve (weeks to months)

Episcleritis Diagnosis: Pinpointing It

• Clinical Diagnosis: Based on history (acute onset, mild pain) & signs.
• Slit-lamp Exam: Sectoral/diffuse redness from engorged superficial episcleral vessels. No scleral edema or bluish hue.
• Phenylephrine Test: 2.5% or 10% drops blanch episcleral vessels (key vs. scleritis).

• Differential Diagnosis (DDx):
  • Episcleritis vs. Scleritis:

    Feature	Episcleritis	Scleritis
    Pain	Mild, discomfort	Severe, boring, radiates
    Blanching (Phe)	Yes	No
    Vision	Normal	Often ↓
    Photophobia	Mild / Absent	Moderate to Severe
    Color	Bright red	Bluish-red, violaceous
    Tenderness	Mild	Exquisite

  • Other DDx: Conjunctivitis (discharge, itch), Keratitis (corneal signs), Anterior Uveitis (cells/flare, miosis).

⭐ The absence of severe, boring pain and preservation of vision are crucial in differentiating episcleritis from scleritis.

• Investigations: Usually not needed. Consider for recurrent/atypical cases (ESR, CRP, RF, ANA) if systemic disease suspected.

Episcleritis Management: Soothing the Sclera

Often self-limiting (resolves in 1-2 weeks).

• Mild cases: Lubricating eye drops, cold compresses.
• Moderate/Severe/Persistent:
  • Topical NSAIDs (e.g., ketorolac 0.5%, diclofenac 0.1%).
  • Oral NSAIDs (e.g., ibuprofen 400-600mg TID, indomethacin 25-50mg TID).
• Severe/Refractory: Topical corticosteroids (e.g., loteprednol, fluorometholone 0.1%) - short-term, with caution (⚠️ IOP ↑, cataract); taper slowly.
• Treat underlying systemic disease if present.
• Recurrences are common.

⭐ Oral NSAIDs are the mainstay of treatment for symptomatic or nodular episcleritis not responding to topical measures.

High‑Yield Points - ⚡ Biggest Takeaways

• Benign, self-limiting inflammation of the episclera; vision remains unaffected.
• Key symptom: Sectoral (most common) or diffuse bright red eye, mild discomfort; no pain on eye movement.
• Crucially blanches with topical phenylephrine (2.5% or 10%), differentiating it from scleritis.
• Two forms: Simple (80%, diffuse/sectoral) and Nodular (20%, movable, tender, localized nodule).
• Often idiopathic; can be linked to systemic diseases (e.g., rheumatoid arthritis, IBD, gout).
• Typically self-resolves; treatment includes artificial tears, topical NSAIDs, or mild corticosteroids for symptoms.
• Recurrences are common, but prognosis is excellent with no long-term sequelae typically seen.