What is the likely cause of eye redness without pain or drainage and swelling to the inner canthus of the lower lid after rubbing?

Eye Redness with Inner Canthus Swelling After Rubbing

This presentation most likely represents mechanical trauma from rubbing causing localized conjunctival irritation and edema, possibly with underlying mucus fishing syndrome or conjunctival chalasis, but you must rule out a blocked nasolacrimal duct or early dacryocystitis if the swelling is truly at the inner canthus near the lacrimal sac. 1

Most Likely Diagnosis

Mechanical conjunctival trauma from rubbing is the primary consideration given the clear temporal relationship and absence of pain or discharge. 1

• The inner canthus lower lid location suggests either conjunctival chalasis (redundant conjunctiva that can become edematous with minor trauma) or localized conjunctival edema from direct mechanical irritation 1
• Mucus fishing syndrome should be considered if there is a pattern of repetitive rubbing to remove mucus, creating a cyclical inflammation with conjunctival injection and staining of the inferior fornix 1
• The absence of pain, discharge, or other inflammatory signs makes infectious or severe inflammatory causes unlikely 2, 3

Critical Red Flags to Exclude

Before assuming benign mechanical trauma, you must actively exclude:

• Dacryocystitis or nasolacrimal duct obstruction: If the swelling is truly medial to the punctum over the lacrimal sac area (not just the conjunctiva), this represents a different pathology requiring different management 2
• Preseptal cellulitis: Any warmth, tenderness, or progression of swelling requires urgent evaluation 4
• Malignancy masquerading as inflammation: Chronic unilateral presentation unresponsive to conservative measures (especially in elderly patients) warrants biopsy consideration for sebaceous carcinoma 1, 5

Immediate Management Algorithm

Step 1: Confirm the anatomic location of swelling

• If swelling is over the lacrimal sac (medial to punctum, below medial canthal tendon), consider nasolacrimal system pathology 2
• If swelling is conjunctival (on the globe or lower lid conjunctiva), proceed with mechanical trauma management 1

Step 2: Conservative management for mechanical trauma

• Stop all rubbing immediately - this is the most critical intervention 1
• Apply cool compresses (not warm) to reduce acute edema 1
• Use preservative-free artificial tears frequently to address any underlying irritation driving the rubbing behavior 1
• Avoid topical vasoconstrictors, which provide only cosmetic improvement without addressing the underlying cause 2

Step 3: Address underlying triggers

• Evaluate for dry eye disease, allergic conjunctivitis, or blepharitis that may be causing the initial irritation prompting rubbing 1
• If mucoid discharge is present, consider mucus fishing syndrome and counsel extensively on breaking the cycle of mechanical removal 1
• Assess for conjunctival chalasis (redundant conjunctiva) which predisposes to chronic irritation and rubbing 1

Follow-up and Warning Signs

Return immediately if:

• Pain develops (suggests corneal involvement or infection) 2, 3
• Vision changes occur 4, 2
• Purulent discharge appears (suggests secondary bacterial infection) 2
• Swelling worsens or becomes warm/tender (suggests cellulitis) 4
• No improvement within 48-72 hours of stopping rubbing 1

Routine follow-up in 1-2 weeks if:

• Symptoms persist despite conservative measures 1
• Pattern suggests chronic/recurrent issue requiring evaluation for underlying causes 1
• Unilateral chronic presentation (to exclude malignancy) 1, 5

Common Pitfalls to Avoid

• Do not prescribe topical antibiotics empirically without evidence of infection (no discharge, no pain) - this only adds preservative exposure and potential toxicity 1, 6
• Do not use topical corticosteroids without slit-lamp examination to rule out corneal pathology, as steroids can worsen herpetic or fungal infections and cause glaucoma 1, 4
• Do not dismiss chronic unilateral cases as simple irritation - sebaceous carcinoma can present as chronic unresponsive unilateral inflammation 1, 5
• Do not confuse conjunctival edema with lacrimal sac pathology - the management differs significantly 2