GELATIN-INDUCED VACCINE ANAPHYLAXIS MISATTRIBUTED TO EGG ALLERGY

Abstract

Introduction Vaccine-related anaphylaxis is rare, occurring at a rate of 1 per million vaccine doses. All suspected anaphylactic reactions should be evaluated with allergy testing to both the vaccine and its components. We report on a case of anaphylaxis following both 12- and 15-month immunizations. Case Description A 17-month old male was referred for evaluation of anaphylaxis to vaccines. At 12 months of age he received initial doses of Influenza, MMR, Hepatitis A, and Pneumococcal 13-valent vaccines. Fifteen minutes following administration he developed coughing, pruritus, and facial/lip angioedema. He was evaluated in an ED and received intramuscular epinephrine for presumed influenza vaccine anaphylaxis secondary to egg hypersensitivity. Three months later he developed cough and facial/lip angioedema within five minutes of his 15-month immunizations (Varicella, DTaP, and Haemophilus B vaccines). Skin testing was positive for Gelatin (11 mm), Egg (9 mm), MMR (5 mm), and Varicella (9 mm), and negative to Influenza (3 mm) with appropriate histamine and saline controls. RAST testing was positive to Bovine Gelatin (25.1 kU/L) and negative to Egg ( Discussion A previous study of MMR vaccine anaphylaxis found 27% of affected patients had anti-gelatin IgE, while none reported gelatin food allergy. MMR, Varicella, Zoster, and Rabies vaccines contain >10,000μg of gelatin/dose with much smaller amounts in influenza vaccines. We concluded that our patient was sensitized to gelatin, and reacted to gelatin-containing vaccines. Proper allergy evaluation is essential following vaccine-related reactions, as unnecessary avoidance can be associated with serious health consequences.