Delayed hypersensitivity to brimonidine tartrate 0.2% associated with high intraocular pressure

To report the late presentation of an allergic reaction to brimonidine tartrate 0.2% associated with an elevation of intraocular pressure.

During a 6-month period six Caucasian patients (three were male), with primary open angle glaucoma (POAG) or ocular hypertension, with an allergic reaction to brimonidine tartrate eye drops were identified. Brimonidine was initiated as additional medical therapy in four patients and monotherapy in two patients. The median age of the patients was 67 years (range 57-73 years).

There were nine eyes with a follicular conjunctivitis; three patients received brimonidine in one eye only. In two patients an additional redness of the periocular skin was present. The median duration on brimonidine therapy before the onset of the allergic reaction was 12 months (range 5-15 months). The median intraocular pressure (IOP) before the onset of the allergy was 18 mmHg (range 16-21 mmHg). There was a significant elevation of IOP at the time of the allergy with a median IOP of 28 mmHg (range 20-44 mmHg) (P = 0.007, Wilcoxon sign rank test). The cessation of brimonidine allowed the resolution of the allergic reaction. The intraocular pressure was then controlled with alternative medication in eight eyes. One patient went on to have filtering surgery.

A delayed hypersensitivity reaction to brimonidine tartrate eye drops resembles a viral follicular conjunctivitis. It is imperative that it is recognised as such, as it may occur many months after brimonidine is initiated. This allergy has been found to be associated with a loss of control of the IOP. Though this is a small cohort of patients, it is not unreasonable to suggest that patients on brimonidine eye drops should be instructed to report promptly to their ophthalmologist the onset of redness of their eyes so that their glaucoma control may be reassessed.