Scleritis

Description

• Scleritis is a painful, inflammatory process of the sclera, part of the eye’s outer coat.
  • Categorized into anterior or posterior and diffuse, nodular, or necrotizing
  • Commonly associated with systemic disorders
  • Potentially vision threatening
• In contrast, episcleritis is a self-limited inflammation of the superficial episclera with only mild discomfort.
• System(s) affected: ocular

Epidemiology

• Mean age is 54 years (ranges from 12 to 96 years).
• Predominant sex: female > male (1.6:1)

Incidence
Estimated to be 6 cases per 100,000 people in the general population

Prevalence

• Anterior scleritis, about 94% of cases (1)
  • Diffuse anterior scleritis, about 75% (most common)
• Remaining 6% have posterior scleritis.

Etiology and Pathophysiology

• Frequently associated with a systemic illness (1)[B]
  • Most commonly associated with rheumatoid arthritis
  • In about 38% of cases, scleritis is the presenting manifestation of an underlying systemic disorder.
  • Necrotizing scleritis has the highest association with systemic disease.
• Other etiologies
  • Proposed pathogenesis is dependent on type of scleritis. In necrotizing scleritis, the predominant mechanism is likely due to the activity of matrix metalloproteinases.
  • Drug-induced scleritis has been reported in patients on bisphosphonate therapy.
  • Surgically induced necrotizing scleritis is exceedingly rare and occurs after multiple surgeries.
  • Infectious scleritis occurs most commonly after surgical trauma, and Pseudomonas aeruginosa in poorly controlled diabetic patients is the most common causative organism (2)[B].

Risk Factors

Individuals with autoimmune disorders are most at risk.

Commonly Associated Conditions

• Rheumatoid arthritis (most common)
• Sjögren syndrome
• Granulomatosis with polyangiitis
• HLA-B27–associated ankylosing spondylitis
• Systemic lupus erythematosus
• Behçet disease
• Juvenile idiopathic arthritis
• Cogan disease
• Relapsing polychondritis
• Polyarteritis nodosa
• Sarcoidosis
• Inflammatory bowel disease
• Herpes zoster, herpes simplex
• HIV, syphilis, Lyme disease, tuberculosis