Oropharyngeal swelling following a ragweed sublingual immunotherapy

Abstract Background: Sublingual immunotherapy (SLIT) is widely accepted as a safe and effective treatment for allergic rhinitis. Despite severe local and systemic reactions following SLIT are reported to be rare, it is important for patients to be educated and monitored for potential risks throughout treatment. This report presents the first documented case of severe oropharyngeal swelling following SLIT, which necessitated epinephrine treatment and termination of therapy, representing a previously unreported severe local reaction. Case Presentation: A 30-year-old man with a history of severe seasonal allergic rhinoconjunctivitis and shellfish allergy presented with severe allergic reaction to ragweed SLIT (Ragwitek). The patient had previously received grass subcutaneous immunotherapy and birch SLIT, both of which were well tolerated. On day 9 of Ragwitek SLIT, the patient experienced oropharyngeal swelling, dyspnea, and dysphagia within minutes following administration of therapy, which required epinephrine treatment to alleviate symptoms. The patient had also experienced upper respiratory tract infection symptoms a few days prior which may have exacerbated the severity of the reaction. Conclusions: This case highlights an occurrence of a rare severe local reaction following SLIT and emphasizes the importance of patient education and close monitoring, especially in those presenting with recurrent local swelling following SLIT. In addition, counselling these patients about the potential risk of oropharyngeal swelling and consideration for prescribing an epinephrine autoinjector is recommended.