ABSTRACT
Alcaftadine is a H1 histamine receptor antagonist indicated for the prevention of itching associated with allergic conjunctivitis. A 51-year-old woman had been prescribed alcaftadine 0.25% for allergic conjunctivitis. After the second application, both eyelids became swollen, and erythematous changes were evident. On slit-lamp examination, conjunctival injection was noted in the absence of conjunctival swelling or any other findings. Fundus examination was unremarkable. A – rather amateurish – patch test with the commercial alcaftadine 0.25% was positive at D2. The possibly allergenic ingredients benzalkonium chloride and edetate disodium were not tested, but these were also present in 2 other ophthalmic preparations that were patch tested and found to be negative.
