💡 Pearl: Topical phenylephrine (2.5–10%) blanches episcleritis vessels (redness fades) ✅ but has no effect on deeper scleral vessels in scleritis ❌.

👁️ About

✨ Benign, usually self-limiting inflammatory condition of the episcleral membrane.
🧩 Uncertain aetiology; inflammation lies between conjunctiva and sclera.

🦠 Aetiology

Often idiopathic (no clear cause).
📌 Sometimes linked to systemic autoimmune disease (RA, IBD, SLE, vasculitis) - though less so than scleritis.

🧾 Clinical

⏱️ Acute onset focal redness and mild discomfort (not severe pain).
👍 Much less severe than scleritis (patients are unwell with scleritis, but not here).
👁️ Mild irritation, tearing; visual acuity, cornea, and pupil are normal.
📍 Localised redness around the conjunctiva - often sectoral.

🔍 Investigations

💉 Phenylephrine blanching test: episcleral vessels constrict → redness resolves; scleral vessels remain red in scleritis.
Systemic workup rarely needed unless recurrent or atypical.

⚖️ Differentials

🔥 Scleritis: Severe boring pain (may wake patient at night), tender to touch, deeper violaceous hue.
👁️‍🗨️ Conjunctivitis: More diffuse redness + discharge; tarsal conjunctiva involved.
🌵 Pterygium (inflamed): Raised triangular nasal lesion, localised redness, may show punctate fluorescein staining.

👁️ Episcleritis vs Scleritis vs Scleromalacia Perforans

Feature	Episcleritis	Scleritis	Scleromalacia Perforans
🔥 Pain	Mild discomfort or none	Severe, deep, boring pain that may radiate to the jaw, brow, or temple	Painless ⚠️
🔴 Redness	Sectoral or diffuse redness	Diffuse, deep violaceous or dusky redness	Minimal redness despite severe disease
🎯 Vessel appearance	Superficial episcleral vessels	Deep scleral vessels with a purple-blue hue	Marked scleral thinning with visible underlying uveal tissue giving a blue-grey appearance
💧 Blanching with phenylephrine	Yes – superficial vessels blanch	No – deep scleral vessels do not blanch	No
👁️ Visual acuity	Usually normal	May be reduced	May be reduced
🧬 Underlying cause	Often idiopathic; may be associated with mild systemic disease	Often autoimmune, especially rheumatoid arthritis or systemic vasculitis	Strongly associated with long-standing rheumatoid arthritis
⚠️ Degree of inflammation	Mild, superficial inflammation	Marked deep inflammation	Minimal visible inflammation despite necrotising disease
🪨 Structural damage	None	Possible scleral thinning and necrosis	Severe scleral thinning with scleral “melting”
💥 Complications	Rare	Vision loss, keratitis, uveitis, scleral thinning, perforation	Globe rupture and permanent visual loss 🚨
💊 Treatment	Usually self-limiting; lubricants or oral NSAIDs if symptomatic	Systemic NSAIDs, corticosteroids, or immunosuppressive therapy depending on severity	Urgent systemic immunosuppression; may require scleral grafting
🚨 Urgency	Low	Urgent ophthalmology review	Ophthalmic emergency

🧠 Exam Tips

📌 Episcleritis is benign, superficial, and usually only mildly uncomfortable.
📌 Scleritis causes severe pain and is often linked to systemic autoimmune disease.
📌 Scleromalacia perforans is the classic painless blue sclera seen in long-standing rheumatoid arthritis.
📌 The absence of pain in scleromalacia perforans is a classic exam trap — it is often the most severe of the three.
📌 Phenylephrine blanching helps distinguish episcleritis from deeper scleral disease.

💊 Management

💧 Frequent preservative-free lubricating drops, gels, or ointments (1st line).
😎 Minimise sun, wind, and air-conditioning exposure.
💊 Oral NSAIDs may help with symptoms.
👨‍⚕️ Ophthalmology referral if recurrent, atypical, or concerns.
⚠️ Occasionally topical NSAIDs or mild topical steroids required under specialist supervision.

The content on this website is provided for educational and informational purposes only to support exam preparation (e.g., MLA, MRCP, USMLE) and learning. This is NOT medical advice, diagnosis, treatment, or professional guidance. It does not replace consultation with a qualified healthcare professional, official guidelines (e.g., NICE, GMC, BNF), or supervised clinical practice. Always verify information with current, authoritative sources. Makindo and its contributors accept no liability for any reliance on this content, including errors, omissions, or any resulting harm, loss, or consequences. By using this site, you agree to these terms.

Episcleritis