Chicken egg protein allergyT78.1

Besides cow's milk allergy, chicken egg protein allergy is the most common food allergy in children (about 6% of all babies are allergic to chicken egg protein in baby food). In most cases, an immediate allergic reaction with symptoms similar to those of cow's milk allergy occurs. In adults, the hen's egg allergy is occasionally preceded by inhalation sesibilisation (cf. bird-egg syndrome).

As with cow's milk allergy, the prognosis is good in infants and toddlers. Possibility of cross-reaction with chicken meat:

The most important chicken egg allergens are ovomucoid (Gal d 1) and ovalbumin (Gal d 2), which accounts for 54% of total protein.

The egg of the chicken (Gallus domesticus) consists of egg white and egg yolk. Egg white contains 9-11% protein in addition to 87-89% water. The yolk contains 50% water, 32-35% lipids and 16% proteins. The sensitization by egg white is the main focus. By means of crossed immune electrophoresis at least 24 antigenic components could be detected. The allergologically most important allergens in a hen's egg (varied according to I Reese) are:

clear as a hen's egg:

• Gal d 1 ovomucoid (together with ovalbumin the most important allergens)
• Gal d 2 Ovalbumin
• Gal d 3 Ovotransferrin
• Gal d 4 Lysozyme C
• Gal d 5 Serum albumin

Chicken egg yellow:

• Gal d 5 Serum albumin
• Gal d 6 YGP42 35 kDa

Rare allergens

• Gal d 7 Myosin light chain
• Gal d 8 alpha-parvalbumin
• Gal d 9 Enolase
• Gal d 10 Aldolase
  

The clinical symptoms can be of varying intensity in children. Thus with gastrointestinal complaints, reactions on the part of the respiratory tract, the skin and the circulation (up to anaphylactic shock) (Jäger L et al. 2001).

Egg allergy, which occurs in infancy or toddlerhood, has a good prognosis. It usually disappears in the course of a few years.

• Chicken eggs contain several protein components. The most important in allergological terms is the heat-labile ovalbumin. Other proteins are ovomucoid, ovotransferrin, lysozyme, livetine. Ovomukoid is heat stable and persists at temperatures above 100°C. The other substances are destroyed at 80-100°C. Patients with ovomucoid sensitization must not eat eggs (not even cooked). However, other proteins in chicken egg white are heat stable. As with cow's milk, sensitization with chicken egg protein is already possible via the mother's milk, so that violent reactions can already occur at the first contact with food containing eggs. The symptoms correspond to the immediate reaction in the case of a cow's milk allergy.
• Chicken protein is present in the following foods and other products (often in a hidden form):
  • Chicken eggs in any form
  • Baked goods such as bread, rolls, cakes, biscuits
  • Pasta
  • Meat and sausage products
  • Soups, sauces, mayonnaise
  • Ready meals
  • jar meals for babies
  • in ready meals as a refining and binding agent
  • Milk ice cream
  • sweets such as candies, pralines, cotton candy
  • margarine preparations.
• The following terms on food descriptions may indicate the use of chicken egg:
  • E 322
  • Emulsifiers
  • Foreign protein
  • Lecithin
  • Protein
  • animal protein.
• Egg can also be used in non-food products (e.g. hair shampoo).
• Some vaccines such as influenza and yellow fever vaccines, which are produced in chicken embryos, may contain chicken egg protein components. Here, vaccination is not excluded in case of chicken egg protein allergy, but should be given under special precautions, possibly under hospitalized conditions. According to recent data, the risk of systemic reactions appears to be low (Turner PJ 2015). In children with known bronchial asthma, vaccination did not lead to a worsening of the espiratory situation.
• Vaccines grown on chicken fibroblasts (MMR, rabies, TBE) contain at best barely detectable traces of chicken egg protein. These vaccinations are often tolerated without problems even in the presence of a chicken egg protein allergy (seevaccination chicken egg protein allergy).

1. Jäger L et al (2001) Food allergens. In Jäger L et al (eds) Food allergies and intolerances. Urban&Fischer Verlag p.161
2. Marseglia A et al. (2013) Outcome of oral provocation test in egg-sensitive children receiving semi-fat hard cheese Grana Padano PDO (protected designation of origin) containing, or not, lysozyme. Eur J Nutr 52:877-883.
3. Reese I et al (2015) Allergy to cow's milk and hen's egg: what does molecular allergy diagnostics offer? Allergo J Int 24: 34-41
4. Turner PJ et al (2015) Safety of live attenuated influenza vaccine in young people with egg allergy: multicentre prospective cohort study. BMJ 351:h6291.
5. Wollenberg A, Vogel S, Renner ED (2010) Vaccinations in atopic dermatitis and other chronic inflammatory skin diseases. Dermatologist 61: 985-993