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Paper text:
there are divergent results of early egg introduction on the subsequent development of egg sensitization , as noted in the jama article by ierodiakonou et al.1 in their meta - analysis of five trials with 1915 participants , the study showed that the egg introduction between 4 and 6 months of age was associated with a lower risk of egg allergy compared to later introduction ( relative risk [ rr]=0.56 , p=0.009 ) .
in contrast though , four trials with 1786 participants showed no association between timing of egg introduction and egg sensitization.1 sensitization and development of allergy are separate conditions .
one of the difficulties in the interpretation of egg introduction studies may be the form of the egg protein itself .
one of the first clinical studies of egg introduction introduced egg yolk to infants either before 3 weeks of age or after 6 months of age.2 the authors reported in both groups that infants developed allergic disease and that respiratory symptoms were common ( 6/13 ) .
recently , two studies of egg introduction highlight that further study is needed to identify whether a subset of infants may benefit from early introduction of egg protein and whether the form of egg impacts the development of allergic disease . a study by bellach et al found no evidence that egg white powder ( vernum ) introduced at 46 months of age prevents hen s egg sensitization or allergy.3 the authors report that among infants screened for the study , 16 were identified to already have responses to egg food challenge and that among these infants , 10 had anaphylactic reactions involving two organ systems .
four of the 16 infants had involvement of the respiratory or cardiovascular systems . among the 383 infants
at 12 months of life , 5.6% in the early introduction group and 2.6% in the placebo group demonstrated egg sensitization ( p=0.24 ) .
this study showed that egg white powder used in early introduction did not significantly modify sensitization at 12 months of age . in a study of 319 infants ,
randomized to receive whole egg powder ( n=165 ) between 4 and 6 months of age , there were fewer infants with egg white sensitization among the early introduction group ( 11% ) versus control group ( 20% , p<0.0001 ) . in this study
, 14 infants reacted to egg within 1 week of early introduction , despite a negative egg white skin test.4 in this study , whole egg powder was effective in reducing the sensitization to egg white at 12 months of age .
a subset of infants in the early introduction group or during food challenge screening will develop a clinical reaction .
there are divergent results available regarding the usefulness of early egg introduction , but more studies comparing egg white , egg yolk , and whole egg powder may yield further insight on the potential modification of allergic responses to hen s egg .
the use of egg protein preparations in clinical trials to reduce the incidence of egg allergy among infants includes a number of preparations of egg . 
 these include whole egg , egg white protein , and egg yolk preparations . 
 the study of the differential immune responses to these allergenic proteins in comparison is suggested as a future research area of investigation .