Successful Treatment Using Etanercept in a Patient with Enthesitis-Related Arthritis Who Had Late Allergic Reaction to Adalimumab

Biological agents are considered important therapies and are increasingly used in the treatment of a range of rheumatological and inflammatory diseases. Nevertheless, the prevalent use of these treatments has been associated with increased incidence of drug-induced hypersensitivity reactions (HSR). A 15-year-old patient with enthesitis-related arthritis developed late HSR after the use of adalimumab. Consequently, etanercept was used as an alternative treatment. Etanercept was administered subcutaneously through a single dose without any reaction upon examination using skin tests (skin prick test, intradermal test, and patch test) against likely cross-reactions given that both adalimumab and etanercept were anti-tumor necrosis factor (TNF) agents. Currently, TNF-α inhibitors find widespread use. Caution is required against HSR reactions, including systemic or local injection site reactions, although they are generally considered safe to use.