Egg allergy is a common allergy. Egg allergy can develop at any age. However, it is most common in the first year of life. It is less common in older children.
Allergic reactions to egg (IgE-antibody mediated) usually begin within minutes to 1 – 2 hours after eating eggs. Certain individuals may react to inhaling “egg fumes” or to skin contact. The symptoms may involve the:
- SKIN – urticaria, atopic eczema, contact urticaria, angioedema
- GASTROINTESTINAL TRACT – abdominal cramps, nausea, and vomiting
- RESPIRATORY TRACT – asthma, allergic rhinitis
Anaphylaxis is a rare but most serious manifestation of egg allergy.
How is egg-allergy diagnosed?
The diagnosis may be easy if the person exhibits the same symptoms after eating egg within minutes or 1 – 2 hours later. It may be difficult if the person is exposed to “hidden” sources of egg such as contamination of a safe food with egg by utensils or equipment, misleading labels and ingredient switching. Eggs may be “hidden” in processed foods (Table1), shampoos, certain beers (as a foaming agent) or in wine and coffee.
Skin prick testing or blood tests for egg allergy may be helpful in detecting IgE antibodies to egg white. Recurrence of symptoms after challenges with egg confirms the diagnosis.
The first step in treatment is strict avoidance of all forms of egg, including hidden sources.
Table 2 lists ingredients that indicate the presence of egg protein. Any product which contains one of these ingredients must be avoided – careful reading of food labels is thus of utmost importance. Food selection guidelines for an egg-free diet must be drawn-up in collaboration with a dietician to ensure nutritional adequacy and adherence to the diet.
Can egg allergy be ‘outgrown’?
Sensitive individuals need not avoid eggs for life. Egg allergy usually subsides before 7 years of age; it disappears in most children by the fourth or fifth year of life; about one-third of individuals have clinical sensitivity that lasts over 6 years.
Is it safe to immunize children with egg-allergy?
- Measles and MMR vaccine
Measles and MMR vaccines are as safe as any other vaccine and an allergy to egg should not delay measles immunization. Persons with mild reactions to egg may be given either of these vaccines without prior skin testing. The rarely reported adverse reactions to MMR (measles) vaccine in fact have occurred mainly in children who are not allergic to eggs; the reactions are most likely explained by the gelatine or antibiotic (Neomycin) contained in the vaccine. As a precaution, it is recommended that egg-allergic children who have experienced serious reactions to egg be immunized with measles or MMR under supervision of a specialist. Children with milder forms of allergy to eggs can be safely vaccinated without any additional precautions.
- Yellow fever and influenza vaccines
Persons with severe allergy to egg should consult a specialist prior to immunization against yellow fever – they require skin prick testing with the vaccine. Influenza vaccine is generally not recommended to such persons because of a risk of allergic reactions and the likely needs for yearly immunization.