Episcleritis

Episcleritis is a benign, self-limiting inflammation of the episclera, the thin vascular layer between the conjunctiva and the sclera. It causes sectoral or diffuse redness with mild discomfort and does not threaten vision. It is most common in young adults (peak 20 to 50 years) and more frequent in women, and it frequently recurs. It must be distinguished from scleritis, which is painful and vision threatening.

• Types: simple (sectoral or diffuse redness; about 70 percent) and nodular (a localised, mobile, raised, tender nodule; about 30 percent).
• Idiopathic in roughly two thirds. Systemic associations are found in about 25 to 30 percent: rheumatoid arthritis, spondyloarthropathies, inflammatory bowel disease, systemic lupus erythematosus, gout, rosacea, atopy, herpes zoster, syphilis, tuberculosis, Lyme disease, Behçet disease.
• It resolves spontaneously in 1 to 3 weeks; nodular episcleritis lasts longer (up to 4 to 6 weeks). Recurrences are common (about 60 percent) and may be annual or related to stress, hormones or season.
• Complications are rare: mild corneal involvement, uveitis (<10 percent), and, very rarely, progression to scleritis.

• Sudden redness of one or both eyes, mild burning, grittiness, tenderness, tearing, mild photophobia; mild or no pain; no discharge; vision normal.
• Examination: radial, salmon pink episcleral vessels engorged in a sector or diffusely; a mobile nodule in the nodular form; the vessels move with the conjunctiva and blanch with topical phenylephrine 2.5 percent; clear cornea; no anterior chamber cells (or minimal); no scleral thinning; normal pupils and intraocular pressure.
• Red flags (suggest scleritis or other disease): severe boring pain radiating to the face or jaw, pain waking from sleep, pain on eye movement, violaceous (bluish red) hue in daylight, vessels that do not blanch with phenylephrine 10 percent, scleral thinning, reduced vision, marked photophobia, anterior chamber cells (uveitis), corneal infiltrate, systemic symptoms (joint pain, rash, cough, haematuria).

• Clinical, by slit lamp examination in natural daylight: assess depth of the injected vessels; apply phenylephrine 2.5 percent (superficial episcleral and conjunctival vessels blanch within 10 to 15 minutes; deep scleral vessels do not).
• Investigations are not needed in a first, typical episode. For recurrent, severe or atypical episodes or systemic symptoms: full blood count, ESR, CRP, rheumatoid factor, antinuclear antibody, uric acid, syphilis serology, chest X-ray, interferon gamma release assay, and HLA B27 if spondyloarthropathy is suspected.
• Differentials: scleritis, conjunctivitis, pingueculitis, uveitis, acute angle closure, subconjunctival haemorrhage, dry eye, keratitis, ocular rosacea, inflamed pterygium.

• Reassurance that it is benign and self-limiting; avoid triggers (dry air, irritants); cold compresses.
• Mild: preservative free lubricants 4 to 6 times daily; resolves in 1 to 3 weeks.
• Moderate to troublesome: topical therapy:
  • Fluorometholone 0.1 percent or loteprednol 0.5 percent, 1 drop four times daily for 1 week then tapered over 1 to 2 weeks (ophthalmic supervision; check intraocular pressure if more than 2 weeks).
  • Topical NSAIDs (ketorolac 0.5 percent four times daily) are less consistently effective.
• Oral NSAIDs for severe or nodular episcleritis or recurrent disease: ibuprofen 400 mg three times daily with food for 5 to 7 days, or flurbiprofen 100 mg three times daily, or naproxen 500 mg twice daily; use with gastric protection (omeprazole 20 mg daily) in at risk patients; avoid in renal impairment, peptic ulcer disease, anticoagulation and pregnancy.
• Treat identified systemic disease and rosacea (doxycycline 100 mg daily for several weeks, lid hygiene).
• Recurrent episodes: review triggers, seek systemic associations, consider prophylactic lubricants.
• Review at 1 to 2 weeks if not settling; refer to ophthalmology if pain intensifies, vision falls, vessels do not blanch, or the diagnosis is uncertain.