Contact allergy to topical ophthalmic medications: A retrospective single-centre study of three decades.

Background: The prevalence of contact allergy to various ophthalmic medications appears to be rare; however, data on culprits, clinical relevance of sensitizations, and changes in frequency within recent decades are limited.

Objective: This study aimed to investigate the clinical relevance, risk factors, and prevalence of contact allergy to topical ophthalmic medications in patients suspected of allergic contact dermatitis to ophthalmic medication.

Methods: We retrospectively analysed patch test results and clinical data for 754 patients patch-tested with an ophthalmic medication series at our tertiary referral centre between January 1992 and December 2022.

Results: In total, 37.5% (283/754) of patch-tested patients had a contact allergy to at least one ophthalmic allergen, with 87.3% (247) being clinically relevant sensitization. Phenylephrine (31.8%, 192/604), povidone-iodine (29%, 27/93), and tobramycin (23%, 46/200) were the most important sensitizers. The incidence of contact allergies increased significantly in a linear manner (p = 0.008) from 20% to 44.1% within the study period. Male sex and age above 40 were risk factors for contact allergy to ophthalmic medication.

Conclusions: One third of patch tested patients had allergic contact dermatitis to ophthalmic medication, particularly phenylephrine. Male sex and age above 40 years were independent risk factors and drove the linear increase in contact allergy to ophthalmic medications within the past 31 years.