Egg allergy

Egg allergy is one of the more common pediatric food allergies. It typically affects just 0.5 percent of the pediatric population (less than 1 of every 100 children) and 5 of every 100 children with allergies. Reactions to egg can vary from life-threatening anaphylaxis to atopic dermatitis (eczema) to hives.

Food allergies are diagnosed by physical examination, previous experience, and allergy testing. There are two types of allergy testing: skin testing and blood testing for specific antibodies to eggs (commonly called RAST testing). Each test has advantages and disadvantages. In general, if you do not have a reaction in either test, you do not have an allergy to egg. However, the blood test can be negative in about 5 of every 100 children who actually do have an egg allergy. A positive blood or skin test indicates a potential to react to egg, and the larger the skin or blood test, the more likely it is that a reaction will occur.

Egg allergies and vaccines

Because influenza and yellow fever vaccines are both made in eggs, egg proteins (primarily ovalbumin) are present in the final products.

• Yellow fever vaccine — In the case of the yellow fever vaccine, quantities are sufficient to cause allergic reactions in susceptible patients. If you or your child is allergic to eggs and you are interested in getting the yellow fever vaccine, you should make an appointment with an allergist.
• Influenza vaccine — Advances in technology have allowed the quantities in current influenza vaccines given as shots to be so minimal that people with egg allergies can now receive the influenza shot. However, because very low quantities of egg protein are still present, people with egg allergy should remain in the provider’s office for about 30 minutes after receiving the vaccine. Two new influenza vaccines, one made in mammalian cells (not avian cells) and the other made using recombinant DNA technology, are now available for patients with egg allergies.

References

Influenza vaccine

Greenhawt M, Turner PJ, Kelso JM. Administration of influenza vaccines to egg allergic recipients: a practice parameter update 2017. Ann Allergy Asthma Immunol 2018;120:49-52.
The American Academy of Allergy, Asthma and Immunology (AAAAI) and the American College of Allergy, Asthma, and Immunology (ACAAI) jointly established influenza vaccine practice parameters in egg allergic recipients. AAAAI and ACAAI state that there is now strong evidence that individuals with egg allergy, regardless of severity, can safely receive inactivated or live attenuated influenza vaccine and that the presence of egg allergy is not a contraindication to receive either vaccine. Furthermore, influenza vaccine recipients are at no greater risk for a systemic allergic reaction than those without egg allergy, and vaccine providers do not need to ask about the egg allergy status of influenza vaccine recipients.

Turner PJ, Southern J, Andrews NJ, Miller E, Erewyn-Lajeunesse M, et al. Safety of live attenuated influenza vaccine in atopic children with egg allergy. J Allergy Clin Immunol 2015;136:376-81.
The safety of a live attenuated intranasal influenza vaccine (LAIV; Fluenz Tetra 2013-14 season) containing ≤ 0.24 mcg/0.2 mL dose of ovalbumin was investigated in 282 children aged 2-17 years with documented IgE-mediated food allergy to egg or a clinical reaction to egg or both within the past 12 months, including 115 children with reported anaphylaxis to egg and 188 children with asthma or documented wheezing. No systemic allergic reactions occurred. Children with a history of recurrent wheezing or asthma were not more likely to experience any adverse events compared with those without such a history. The authors concluded the use of LAIV appears to be safe for use in children with egg allergy and well tolerated in those with asthma or recurrent wheezing.

Turner PJ, Southern J, Andrews NJ, Miller E, Erewyn-Lajeunesse M, et al. Safety of live attenuated influenza vaccine in young people with egg allergy: multicenter prospective cohort study. BMJ 2015;351:h6291. 
The safety of a live attenuated intranasal influenza vaccine (LAIV; Fluenz Tetra 2014-15 season) containing ≤ 0.24 mcg/0.2 mL dose of ovalbumin was investigated in 779 children aged 2-18 years with documented egg allergy, including 157 with reported anaphylaxis to egg, and 445 children with asthma or documented wheezing. No systemic allergic reactions occurred. The authors concluded that the use of LAIV is associated with a low risk of systemic allergic reactions in young people with egg allergy, and well-tolerated in those with well controlled asthma or recurrent wheezing. 

Webb L, Petersen M, Boden S, LaBelle V, Bird JA, et al. Single-dose influenza vaccination of patients with egg allergy in a multicenter study. J Allergy Clin Immunol 2011;128(1):218-219.
The safety of inactivated (TIV; Fluzone) influenza vaccinations was investigated in 152 patients aged 7 months to 30 years (median age 3 years) with egg allergy, including 34 patients with reported anaphylaxis to egg, during the 2009-2010 influenza season. Thirty-eight separate lots of Fluzone® from 3 different companies were used for vaccination, and up to 50% of the lots may have contained more than 1.2 mcg/mL ovalbumin. No systemic reactions occurred in any patients, including those with severe egg allergy.

James JM, Zeiger RS, Lester MR, Fasano MB, Gern JE, et al. Safe administration of influenza vaccine to patients with egg allergy. J Pediatr 1998; 133(5):624-628.
The safety of inactivated influenza vaccines was evaluated in children aged 6 months and older with egg allergy, including 27 patients with reported anaphylaxis to egg. The influenza vaccines contained three different amounts of egg protein (ovalbumin/ovomucoid; 0.1, 1.2, and 0.02 mcg/mL). No significant allergic reactions occurred. The authors concluded that influenza vaccine containing no more than 1.2 mcg/mL egg protein can be safely administered to patients with severe egg allergy.

Measles-containing vaccine

James JM, Burks AW, Roberson PK, Sampson HA. Safe administration of the measles vaccine to children allergic to eggs. New Engl J Med 1995;332:1262-1266.
The authors administered MMR vaccine, for which measles and mumps components are propagated in chick-embryo-cell cultures, to 54 children aged 12-63 months with documented egg allergy, including 26 with reported anaphylaxis to egg. No immediate or delayed adverse reactions occurred. The authors concluded that MMR vaccine can safely be administered to children with egg allergy, even those with severe hypersensitivity.

Freigang B, Jadavii TP, Freigang DW. Lack of adverse reactions to measles, mumps and rubella vaccine in egg-allergic children. Ann Allergy 1994;73(6):486-488.
MMR vaccine was administered to 500 egg allergic children in an outpatient setting and no anaphylactic reactions occurred. The authors concluded that a history of egg allergy should not be considered a contraindication to receipt of MMR vaccine.

Bruno G, Giampietro PG, Grandolfo ME, Milita O, Businco L. Safety of measles immunization in children with IgE-mediated egg allergy. Lancet 1990;335(8691):739.
The authors administered measles vaccine to 23 children (median age 2 years 5 months) with documented egg allergy. No immediate or delayed systemic adverse reactions occurred.  The authors concluded that measles vaccine can safely be administered to children with documented egg allergy.

Yellow fever vaccine

Smith D, Wong P, Gomez R, White K. Ovalbumin content in the yellow fever vaccine. J Allergy Clin Immunol Pract 2015;3(5):794-795.
Egg hypersensitivity is listed as a contraindication to the receipt of yellow fever vaccine as it is propagated in hen’s eggs, though the ovalbumin content is unknown. The authors tested four lots of the vaccine manufactured in the United States revealing different concentrations of ovalbumin in each lot (2.43-4.42 mcg/mL), all of which were higher than those concentrations contained in influenza vaccines. The authors concluded that skin testing should be performed in patients with egg allergy prior to yellow fever vaccination, as those with a positive skin test should receive the vaccine in graded doses under the close observation of a medical professional trained to recognize and treat anaphylaxis.

Rutkowski K, Ewan PW, Nasser SM. Administration of yellow fever vaccine in patients with egg allergy. Int Arch Allergy Immunol 2013;161:274-278.
Yellow fever vaccine has an anaphylaxis rate that ranges from 0.42 to 1.8 per 100,000 doses with most cases considered to be due to egg allergy. Six subjects with an egg allergy were successfully vaccinated, including four who completed a desensitization. No systemic adverse reactions occurred.

Written by: Jonathan Spergel, MD, PhD
Dr. Spergel is Chief of the Allergy Section and Co-Director of the Center for Pediatric Eosinophilic Disorders at The Children’s Hospital of Philadelphia