Dacryocystitis or Canaliculitis
A swollen medial canthus with discharge is most commonly termed dacryocystitis (infection of the lacrimal sac) or canaliculitis (infection of the lacrimal canaliculus), depending on the precise anatomical location and clinical presentation.
Key Distinguishing Features
Dacryocystitis
- Swelling below the medial canthal tendon (over the lacrimal sac area)
- Tenderness and erythema over the lacrimal sac
- Purulent discharge expressible from the punctum with digital pressure over the sac
- May present acutely with fever and systemic symptoms, or chronically with persistent tearing and discharge
- Can progress to orbital cellulitis if untreated
Canaliculitis
- Swelling at or around the punctum and medial canthus 1, 2
- Pouting (eversion) of the lacrimal punctum - this is a distinctive sign 1
- Discharge from the punctum, often with grainy or concretion-like material 2
- Conjunctival injection and swelling involving the punctal area 1
- Chronic presentation with persistent epiphora and discharge 2, 3
- May have punctal ulceration or tissue necrosis in severe cases 1
Clinical Pitfalls
Canaliculitis is frequently misdiagnosed and overlooked 1 because:
- It can mimic chronic conjunctivitis or blepharitis
- The characteristic punctal pouting may be subtle
- Patients are often treated empirically for conjunctivitis without examining the punctum carefully
Critical Action Points
When evaluating medial canthal swelling with discharge:
- Examine the punctum specifically - look for pouting, erythema, or discharge
- Apply digital pressure over the lacrimal sac - note if purulent material expresses from the punctum
- Assess the location - above vs. below the medial canthal tendon
- Culture any discharge - especially if chronic or unresponsive to initial treatment 1, 2
- Consider unusual organisms in chronic cases - Pseudomonas aeruginosa 1, Serratia marcescens 2, and Campylobacter concisus 3 have been reported
When to Suspect Alternative Diagnoses
In chronic, unresponsive cases despite appropriate antibiotic therapy:
- Ocular adnexal lymphoma should be considered in the differential 4
- Other rare causes include gouty tophus in patients with hyperuricemia 5
- Anatomical variants like supernumerary punctum may present with chronic discharge 6
If a patient has been treated for "chronic dacryocystitis" for months without improvement, surgical exploration and biopsy should be pursued to rule out malignancy 4.