SEVERE ANAPHYLACTIC REACTION TO ALLERGEN IMMUNOTHERAPY WHILE ON A BETA-BLOCKER AND SUCCESSFUL RESUMPTION OF IMMUNOTHERAPY

Introduction Severe systemic reactions can occur with allergen immunotherapy (AIT). Beta-blockers do not increase incidence of anaphylaxis with AIT, but they can affect severity of reaction. Case Description A 57-year-old man with allergic rhinoconjunctivitis presented early August for maintenance AIT injection. He is allergic to grasses, weeds, dust mites, tree pollen, dog, cat and molds but was feeling well. Within three minutes of injection he developed emesis and symptomatic hypotension. Intramuscular epinephrine was promptly administered and he was positioned on the ground on his side to protect his airway and mitigate hypotension. He required three additional doses of epinephrine and normal saline bolus given persistent hypotension. He received nebulized albuterol for bronchospasm with hypoxia. Once stabilized, he was transferred to ICU and discharged after observation overnight. Serum tryptase one hour after symptom onset was 10.9 ng/dL. Upon chart review, his neurologist had recently started propranolol for migraine prophylaxis, though patient cannot recall if he took propranolol prior to his injection. Baseline serum tryptase was 4 ng/dL. After thorough discussion, the patient elected to resume AIT given symptom control, and propranolol was discontinued. He presented to clinic two days after the event and received 20% of his maintenance dose. He reached maintenance dose in the following weeks and will receive injections at two-week intervals for the time being. Discussion This case underscores the importance of carefully screening for beta-blocker use at all AIT visits. It also provides an example of resuming AIT following severe anaphylactic reaction and the relevance of baseline tryptase levels.