Episcleritis & Scleritis Summary

Definitions

  • Episcleritis: Inflammation of episclera (thin layer between conjunctiva and sclera)
  • Scleritis: Inflammation of sclera (white outer wall of eye)

Risk Factors

  • Episcleritis: Usually no underlying systemic disease
  • Scleritis: Often associated with systemic inflammatory diseases (RA most common)

Clinical Features

  • Episcleritis: Redness, irritation, watering; sectoral redness
  • Scleritis: Severe deep pain, tenderness, photophobia, visual disturbance

Diagnosis

  • Phenylephrine test: Blanching in episcleritis, not in scleritis
  • Cotton bud test: Episcleral vessels movable

Management

  • Episcleritis: Referral, artificial tears, topical NSAIDs/steroids
  • Scleritis: Urgent referral, systemic NSAIDs/steroids/immunosuppressants

Complications

  • Episcleritis: Rare
  • Scleritis: Keratitis, scleral thinning, glaucoma, permanent vision loss

Key Differences

  • Pain: Mild in episcleritis vs severe in scleritis
  • Systemic association: Rare in episcleritis vs common in scleritis
  • Visual disturbance: Uncommon in episcleritis vs common in scleritis

Episcleritis & Scleritis

Inflammatory conditions affecting the outer layers of the eye

Overview

Episcleritis

Inflammation of the episclera (a thin layer of tissue that lies between the conjunctiva and the sclera).

Scleritis

Inflammation of the sclera (the white outer wall of the eye).

Risk Factors

Episcleritis

  • Most patients do not have an underlying systemic inflammatory or infectious disease
  • Idiopathic in majority of cases
  • Occasionally associated with rosacea or gout

Scleritis

  • Most patients have an underlying systemic inflammatory or infectious disease
  • Rheumatoid arthritis (most common association)
  • Other connective tissue diseases (SLE, granulomatosis with polyangiitis)
  • Inflammatory bowel disease
  • Infections (herpes zoster, syphilis, tuberculosis)

Clinical Features

Episcleritis

Symptoms
  • Acute onset of redness, irritation and watering of the eye
  • Mild discomfort or grittiness
  • Usually unilateral
Signs
  • Sectoral redness in eye (inflammatory nodule may be present over the area)
  • Episcleral vessels blanch with phenylephrine eye drops
  • Episcleral vessels can be moved with a cotton bud
  • No visual impairment typically

Scleritis

Symptoms
  • Acute onset of severe ocular pain and redness
  • Pain described as 'deep' or 'boring'
  • Pain worse with ocular movement and at night
  • Tender eye
  • Lacrimation
  • Photophobia
  • Visual disturbance
Signs
  • Deep scleral vessel engorgement
  • Bluish purple discolouration of the sclera
  • Pain on ocular palpation
  • Reduced visual acuity
  • Possible scleral thinning or necrosis

Diagnostic Tests

  • Phenylephrine test: 2.5-10% phenylephrine causes blanching of vessels in episcleritis but not in scleritis
  • Cotton bud test: Episcleral vessels can be moved over the sclera with a cotton bud
  • Slit-lamp examination: Essential for proper diagnosis and classification

Management

Episcleritis

  1. Referral to ophthalmology to confirm diagnosis
  2. For patients not bothered by symptoms:
    • Treatment generally not needed
    • Spontaneous resolution over several weeks
  3. For symptomatic patients (in order of use):
    • Artificial tear preparations
    • Topical NSAIDs (e.g., ketorolac)
    • Topical glucocorticoids (short course if severe)
  4. Consider systemic workup if recurrent or bilateral

Scleritis

  1. Urgent referral to ophthalmology
  2. Systemic therapy required:
    • Oral NSAIDs (for mild anterior scleritis)
    • Oral glucocorticoids (mainstay of treatment)
    • Immunosuppressive drugs (for severe or refractory cases)
    • Biologic agents (in specific autoimmune conditions)
  3. Topical steroids may be used adjunctively but are insufficient alone
  4. Comprehensive systemic evaluation for underlying disease
  5. Regular monitoring for complications

Complications

Episcleritis

  • Complications are rare
  • May recur but generally benign course
  • No permanent visual impairment

Scleritis

  • Keratitis
  • Scleral thinning
  • Raised intraocular pressure
  • Globe perforation
  • Glaucoma
  • Cataracts
  • Retinal detachment
  • Permanent visual loss
  • Uveitis

Differential Diagnosis

Condition Key Features Differentiation
Conjunctivitis Diffuse redness, discharge, itching No deep pain, discharge present
Anterior Uveitis Circumlimbal injection, photophobia Cells/flare in anterior chamber, no scleral involvement
Subconjunctival Hemorrhage Bright red, well-demarcated area No pain, no inflammation, resolves spontaneously
Corneal Abrasion/Ulcer Pain, photophobia, foreign body sensation Fluorescein staining positive, corneal involvement

Prognosis

Episcleritis

  • Excellent prognosis
  • Self-limiting (1-3 weeks)
  • Recurrence common but benign
  • No long-term sequelae

Scleritis

  • Variable prognosis depending on type and severity
  • Necrotizing scleritis has poorest prognosis
  • Chronic course with exacerbations
  • Risk of permanent visual impairment
  • Prognosis tied to control of underlying systemic disease