Childhood Egg White Allergy: Raw and Cooked Egg Differences
Two-thirds of children suffering from severe atopic dermatitis demonstrate hypersensitivity to egg white (Sampson, 1992). It is important to improve our understanding of egg white allergies as eggs are highly nutritious sources of protein, so avoiding them as a strategy for the management of allergies can lead to nutritional problems. Studies suggest that many children can tolerate cooked eggs whilst suffering extreme allergic reactions to raw or undercooked eggs.
Allergy to egg white in childrenes New
Eggs are among the top eight of all allergens, and egg white allergy is relatively common in young children. Egg white allergy can cause atopic dermatitis or eczema, and can also cause anaphylactic reactions of varying severity. Patients suffering from egg white allergy may be sensitive to any of four possible egg white proteins: ovomucoid, ovalbumin, ovotransferrin or lysozyme. Fortunately, many children grow out of their egg white allergy, with 68% developing tolerance by the age of 16 (Savage et al).
A study by Urisu et al investigated the allergic response of 38 subjects to different types of egg white in order to determine the importance of the protein ovomucoid in allergic conditions. The researchers found that heated and ovomucoid-depleted egg white elicited less of a response than heated or freeze-dried egg white, suggesting that ovomucoid is the most important allergen in egg white.
Cooked eggs are less allergenic than raw eggses New
Two case studies by Eigenmann describe how patients with a history of atopic dermatitis can tolerate cooked eggs as demonstrated by negative follow-up food challenges but can then suffer serious anaphylactic reactions to raw or undercooked eggs. Subsequent skin prick tests of the patients revealed sensitivity to raw egg, but much weaker reactions to hard boiled egg. It seems that the process of cooking alters the protein structure sufficiently to reduce allergenicity.
Avoiding egg white allergyes New
The American Academy of Pediatrics (AAP) revised its advice regarding the avoidance of the development of food allergy in 2016 in the light of new research (Greer et al, ). Breast feeding for the first four to six months is known to have a protective effect, as does the use of partially hydrolysed (PH) infant formula. There is no evidence to suggest delaying the introduction of egg whites beyond six months protects against the development of egg white allergy.
Management of egg white allergyes New
There is no current treatment for egg allergy, so management consists of dietary avoidance of egg products. The current advice is summarised in a review article by Tey and Heine.
Many sufferers can safely eat cooked egg, indeed des Roches et al reported that 73% of subjects could tolerate baked egg in a cake. Many experts believe that exposure to cooked egg products can actually decrease sensitivity to raw egg leading to an earlier recovery, and some studies provide encouraging evidence that this may indeed be the case (Lemon-Mule et al). However, further randomised trials are required to confirm this, so current advice for sufferers is to avoid egg completely until the allergy is resolved.
The manufacture of some vaccines involves egg products, and such vaccines could be hazardous to children with egg allergy. Influenza and yellow fever vaccines are examples, but the MMR immunization has been shown to be safe for egg-allergic children by three large trials, including one by Fasano et al.