Systemic allergic reaction to galcanezumab (emgality): a case report.

BACKGROUND: A previously unreported systemic reaction to Galcanezumab (Emgality) is described. Galcanezumab is a humanized monoclonal antibody designed to bind to calcitonin gene-related peptide, a neuropeptide associated with neurogenic inflammation during migraine attacks. Although clinical trials showed that Galcanezumab had few adverse reactions (injection site related erythema, pruritus, and swelling), no systemic drug reactions have been noted. CASE REPORT: A 50-year-old female with chronic migraine, mast cell disorder, Hashimoto's disease, positive antinuclear antibody and positive anti-cyclic citrullinated peptide antibody not on immune modulators received the initial dose of galcanezumab 240 mg after failing multiple migraine treatments. The following day, she developed injection site reaction, malar erythema and flu-like symptoms. Symptoms progressed the second day after injection, and she developed swelling in her lips and throat. Intravenous steroid and antihistamines improved airway symptoms, and the remaining symptoms improved after a course of oral steroids. CONCLUSIONS: Delayed system allergic reaction to Galcanezumab requiring emergency intervention may occur. A history of autoimmune disorder may be a predisposing factor.