A Case of Bilateral Keratitis and Bilateral Anterior Uveitis Induced by Pembrolizumab

Purpose: The purpose of this study was to report a case of bilateral keratitis and bilateral anterior uveitis that occurred at different time points after initiating pembrolizumab therapy. Case report: A 70-year-old man was referred to our hospital due to blurred vision and conjunctival injection in his right eye. Initial examination revealed conjunctivalization of the cornea with a corneal ulcer, inflammatory cells in the anterior chamber, and bilateral epiretinal membrane. Because the right-eye symptoms included blurred vision and redness immediately postpembrolizumab administration, a diagnosis of ophthalmic immune-related adverse event (irAE) was made. He was treated with antibiotic and betamethasone eye drops in his right eye. Because skin rashes appeared on his face and upper and lower extremities simultaneous with the ocular symptoms, a diagnosis of a grade 2 dermatological irAE was made based on dermatological findings, and pembrolizumab was discontinued. At 3 weeks postpembrolizumab discontinuation, conjunctival injection with inflammatory cells occurred in his left eye, so a treatment with additional antibiotic and betamethasone eye drops was initiated. At 1 month postpembrolizumab discontinuation, the dermatological irAE (skin rashes) disappeared, with no recurrence of ocular and dermatological irAE for more than 2 years post-treatment. Conclusions: Because anterior uveitis is a widely known adverse event of the checkpoint inhibitor pembrolizumab, ophthalmologists need to be aware whether their patients are on the medication and conduct timely follow-up examinations in cases in which new eye symptoms occur.