Early introduction of egg and egg allergy

An Australian study has shown that introducing cooked egg to infants between 4 to 6 months of age may protect against developing egg allergy (1). This supports the concept of a  'critical window'  between 4-6 months when exposure to potentially allergenic foods may induce immune tolerance and protect against food allergy (2).

The study was undertaken in Melbourne between June 2008 and January 2010 and was part of the HealthNuts study. Its aim was to detemine whether egg allergy in one year old children was associated with duration of breast feeding and/or age of introduction of egg and solids.

Over 2,500 infants were recruited. which took place at the 12 month immunization sessions at clinics. Mothers were interviewed and filled out detailed questionnaires about the duration of breast feeding, when solids were introduced and when egg and egg containing foods were introduced. The infants were given skin prick tests to four foods including egg white and the controls histamine and saline. Those with positive skin prick tests to egg white were given oral food challenges to raw  egg white. Infants considered to be egg allergenic were not given the food challenge.

The study found:-

• infants introduced to egg between 4-6 months had lower risk of egg allergy than those introduced later, even after adjustments for family history of allergy and allergy symptoms
• Infants with a family history of allergy and with eczema were at highest risk
• Lowest risk of allergy was in infants whose first exposure to egg was as cooked egg rather than in egg found in baked goods such as biscuits, cakes
• The duration of breast feeding and  age of introduction of solids were not associated with egg allergy.

The study also showed that current infant feeding recommendations are not being followed. While eggs  are generally recommended for introduction around 10 months, 65% of mothers had introduced then between 4 - 9 months. Dietary Guidelines for Children and Adolescents recommend solids be introduced at 6 months. The study showed that 45% of infants had solids introduced  between 4 to 5 months of age.

The study challenges the practice of delaying introduction of egg to protect against egg allergy, indicating that it may cause an ncrease. These findings may  have  implications for future guidelines on introducing solids. 

References.

1.Koplin JJ, Osborne NJ et al. Can early introduction of egg prevent egg allergy in infants? A population based study. J Allergy Clin Immunol 2010;126(4):807-813

2. Agostini C, Decsi T et al. Complementary Feedinig: A Commentary by the ESPGHAN Committee on Nutrition. J Pediatr Gastroenterol Nutr 2008:46(1):99-110