• Clinical science

Scleritis and episcleritis

Summary

Scleritis is an inflammatory condition that affects the sclera, while episcleritis is an inflammatory condition that affects the episclera. Because the episclera is the outermost layer of the sclera, episcleritis is a more superficial condition. While the etiology of episcleritis is usually idiopathic, scleritis often occurs in individuals with underlying systemic disease (e.g., rheumatoid arthritis, systemic lupus erythematosus). Both conditions can also be caused by infections or reactions to medications. They are diagnosed based on the patient history and physical examination. A search for underlying systemic illness is especially important when scleritis is diagnosed, but it is also warranted in suspected episcleritis if there are other signs of systemic disease present (e.g., arthritis, rash). Systemic treatment with corticosteroids is generally required in necrotizing scleritis, scleritis that does not resolve with NSAIDs, and scleritis affecting the posterior portion of the sclera. In refractory cases, immunosuppressive drugs may be required. Episcleritis typically regresses after 1–2 weeks, and treatment is not necessary in most cases.

Anatomy of the eye

Episcleritis

  • Definition: inflammation of the episclera
  • Epidemiology
    • Mean age: ∼ 45 years
    • >
    • Unilateral in up to 70% of cases
  • Etiology
    • Most commonly idiopathic
    • Associated with underlying systemic disease in a minority of cases (most commonly rheumatoid arthritis)
    • Less common causes
  • Clinical features
    • Acute onset of symptoms
    • Mild eye pain/irritation and watering
    • Eye redness
    • Vision is not affected
  • Subtypes and variants
  • Diagnostics
    • Diagnosed based on patient history and physical examination
    • Vasoconstricting eye drops (phenylephrine) may allow episcleritis to be differentiated from scleritis.
    • Further diagnostics are required if systemic disease is suspected.
  • Treatment
    • Symptomatic treatment (e.g., cold compresses, eye lubrication)
    • In persistent or severe cases: NSAIDs and/or topical steroids
    • Treatment of any underlying conditions
  • Prognosis
    • In most cases, spontaneous regression occurs after 1–2 weeks.
    • Recurrent bouts of the disease may occur every 1–3 months.
    • Rarely progresses to reduced visual acuity

Although episcleritis is usually self-limiting, it manifests similarly to other, less innocuous conditions of the eye (e.g., scleritis, keratitis) that do require treatment. These conditions should be ruled out prior to diagnosing episcleritis (see “Differential diagnoses” below).

Scleritis

In a patient with focal eye pain with tenderness to palpation of the eye, with or without violet discoloration of the sclera, an ophthalmologic consult is warranted!

In order to diagnose scleritis, a workup should be done to evaluate for underlying systemic disease!

Differential diagnoses

Scleritis Episcleritis
Most common etiology
  • Idiopathic
Clinical features
  • Subacute onset
  • Severe pain exacerbated by eye movement
  • Visual disturbances and photophobia
  • Acute onset
  • Mild pain/irritation
  • Eye redness, watering
  • Normal vision, no photophobia
Diagnostics
  • Phenylephrine eye drops → nonblanching
  • Blue coloration of the eye (deep inflammation)
  • Eye changes (e.g., nodules, thinning of the sclera, corneal changes)
  • Signs of systemic illness (e.g., arthritis, rash)
Treatment
  • Typically self-limiting
  • Topical steroids if refractory
Prognosis
  • Permanent partial loss of vision is possible.
  • Rarely progresses to reduced visual acuity

The differential diagnoses listed here are not exhaustive.

last updated 12/06/2019
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