Hypersensitivity to glucagon‐like peptide‐1 receptor agonists: A case of delayed urticaria‐like rash to dulaglutide and literature review

Dulaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist, which stimulates insulin release via activation of GLP-1 receptors on pancreatic beta cells. We report the case of a 45-year-old woman with type 2 diabetes mellitus who started dulaglutide subcutaneously and developed, a few minutes after the fourth administration, a persistent itchy reaction at the injection site, followed, after two more administrations, by a diffuse itchy delayed urticaria-like rash, healed in 7 days after drug interruption. Skin test performed after 3 months from the event demonstrated the culprit role of the drug. Given the limited evidence in literature, there is currently no standardised protocol for testing patients sensitised to one or more glucagon-like peptide-1 receptor agonists. Performing skin tests, especially intradermal tests, is pivotal to confirm the aetiological role of the drug in the suspected hypersensitivity reaction, and possibly to identify an alternative to be proposed before precluding the entire drug class. To the best of our knowledge, this is the first case of systemic hypersensitivity reaction to dulaglutide presenting as a delayed urticaria‐like rash and confirmed by positive skin test.