Dacryocystitis & Canaliculitis

Overview

Infection anywhere along the lacrimal drainage system tends to follow the same logic: an obstruction causes tears to stagnate, and stagnant fluid becomes a culture medium. Acute dacryocystitis and chronic canaliculitis are the two infections that result. They differ in location (sac versus canaliculus), tempo (acute versus indolent), and causative organism, but both are complications of impaired drainage rather than primary infections of otherwise healthy tissue.

Acute Dacryocystitis

Acute dacryocystitis is infection and inflammation of the lacrimal sac, arising secondary to nasolacrimal duct obstruction and the resulting stasis of tears within the sac. It presents with pain, redness, and swelling localized directly over the lacrimal sac at the medial canthus, sometimes with frankly purulent discharge expressible from the punctum on gentle pressure. That maneuver is the regurgitation test, covered further on this site's epiphora page: reflux of mucus or pus with sac palpation confirms nasolacrimal duct obstruction with retained material.

Staphylococcus aureus is the most common causative organism in adults, with streptococcal species also frequently implicated. Both are typical skin and upper respiratory flora, and both find easy purchase in tear fluid once normal drainage stops clearing it. That gram-positive predominance is why first-line systemic antibiotic therapy favors an agent with reliable staphylococcal and streptococcal coverage; co-amoxiclav (amoxicillin-clavulanate) is a standard choice for exactly this reason. Antibiotics treat the acute infection but do nothing for the underlying obstruction. Definitive management of the obstruction itself, often dacryocystorhinostomy, is generally deferred until the acute infection has settled rather than attempted during the inflammatory phase.

Chronic Canaliculitis

Chronic canaliculitis is a far more indolent process than acute dacryocystitis and involves the canaliculus itself rather than the sac. It is easy to misdiagnose: a chronically red, mildly tender, discharging punctal region can look like ordinary conjunctivitis or blepharitis for months before the correct diagnosis is made. The classic causative organism is Actinomyces israelii, a filamentous, gram-positive bacterium that produces characteristic yellowish "sulfur granules," concretions of organisms and debris that accumulate within the canaliculus. Expressible concretions and a "pouting," swollen punctum on exam are the findings that should prompt suspicion of canaliculitis rather than a generic ocular surface infection.

Because the concretions sit within the canaliculus itself, topical or systemic antibiotics alone are usually insufficient. Definitive treatment requires mechanical removal via curettage or canaliculotomy: the physical nidus of infection has to be removed, not just treated from the outside.

Parinaud Oculoglandular Syndrome

Parinaud oculoglandular syndrome is a distinct clinical picture worth distinguishing from simple lacrimal-system infection: a unilateral granulomatous follicular conjunctivitis with regional, classically preauricular, lymphadenopathy. That lymphadenopathy should prompt a search for the syndrome's systemic infectious causes, most classically cat-scratch disease, rather than management as routine conjunctivitis.

Dacryocystography

When the level or nature of a drainage-system problem isn't clear from exam and syringing alone, dacryocystography (DCG) provides direct anatomical visualization: a radiopaque contrast agent is injected into the drainage system and imaged, localizing exactly where an obstruction sits along the punctum-to-nose pathway. It is a targeted study, reserved for cases the clinical exam and bedside syringing haven't already answered. Most straightforward cases of dacryocystitis or canaliculitis are diagnosed clinically, with no need for DCG at all.

A related, purely clinical finding is the lacrimal sac mucocele: a painless swelling at the medial canthus produced by chronic nasolacrimal duct obstruction, in which the sac distends with retained mucus rather than becoming acutely infected. It can still become secondarily infected and evolve into dacryocystitis if left untreated, but on its own it reflects chronic stagnation, not acute bacterial infection.

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