A closer look at allergic contact dermatitis caused by topical ophthalmic medications.

ABSTRACT

BACKGROUND: Allergic contact dermatitis caused by topical ophthalmic medications (OftACD) is frequently difficult to confirm with patch testing and, therefore, it is considered uncommon. METHODS: We collected retrospective data from a cohort of 65 patients with suspected OftACD patch tested in our Dermatology Unit (2005-2021) according to ESCD guidelines, using a series of topical drugs and excipients (Chemotechnique Diagnostics), including betaxolol and timolol 5% pet. kindly supplied by the pharmaceutical industry. Also, frequently used ophthalmic medications as well as patient's own products were also patch tested 'as is' in most patients. RESULTS: Positive patch tests to ophthalmic medications occurred in 44 patients (67.7%) (38F/6M; mean age 63.1 years), with 102 positive reactions. Most positive reactions were associated with active ingredients (n = 56), especially aminoglycoside antibiotics (n = 27), followed by excipients (n = 24) such as sodium metabisulfite (n = 7). There were also positive reactions to topical products tested 'as is' (n = 22), mostly containing beta-blockers, but only five of these reacted to the active ingredient. DISCUSSION: This study reinforces previous findings in OftACD, such as older age of onset, and the importance of antibiotics, contrasting with the progressively lower prevalence of excipients. In addition, it helps raising awareness for the sensitization to beta-blockers, which is probably underestimated. Patch test preparations for the diagnosis of OftACD may require protocol optimization.