Plug-related canaliculitis: a rare or underdiagnosed disease?

Clinical Relevance: Conjunctivitis, chalazion and blepharitis are routinely managed by optometrists. However, it is especially important to consider the diagnosis of canaliculitis in patients with chronic or recurrent conditions.
Background: This study aimed to report the clinical features, radiological findings and treatment outcomes in patients with plug-related canaliculitis.
Methods: This retrospective study included patients with canaliculitis secondary to plug insertion between 2007 and 2020. All data regarding epidemiological characteristics, clinical presentation, isolated microorganisms, computed tomography imaging findings, treatment, and outcomes were analysed.
Results: A total of 20 plug-related canaliculitis from 19 patients (18.3%) among all 109 cases of canaliculitis were identified. All patients with plug-related canaliculitis were females with a past history of lacrimal plug insertion for dry eye (mean age: 58.2 years). Most patients were initially treated as conjunctivitis with the mean time lapse to a diagnosis of 5.2 months. The average time from plug insertion to onset of symptoms was 5.1 years. Eighteen patients underwent canaliculotomy, and one patient received lacrimal irrigation. Plugs were identified in 18 cases, with SmartPlug in 13 cases (72%), followed by EaglePlugTM (two cases), Herrick Lacrimal Plug (two cases), and migrated FCI Painless Plug (1 case). Cultures of discharge, concretions, and/or infected plugs mostly revealed Pseudomonas aeruginosa (42%). Orbital computed tomography in four cases with SmartPlug revealed central radiolucency with surrounding soft-tissue enhancement. No recurrent canaliculitis was observed throughout a mean follow-up period of 13.7 months. No patient needed re-plugging after canaliculotomy and plug removal, with only one required additional lubricants for recurrent dry eye.
Conclusion: Plug-related canaliculitis is often underdiagnosed due to late onset and similar symptoms to common ocular diseases. Awareness of plug insertion history as well as meticulous removal of the plug, concretion and/or granulation tissue is important for early diagnosis and to ensure a good outcome.