Egg allergy

Common.  Associated with eczema.  Can be prevented by early introduction as part of weaning – see EAT study, where 75% of cases prevented where families could stick to protocol.

Mostly mild reaction, 7% anaphylaxis quoted before diagnosis made.  Moderate to severe reactions can occur just from contact, if raw egg has been applied to inflamed nappy rash.

Diagnosis is made clinically.  No investigations are required if reactions mild (not really defined!).  testing “useful” in “mod-severe” reactions (not specified really but does say hospital challenge if “severe vomiting or diarrhoea”).  No cut off given for SPT or IgE although historically 95% PPV at 4mm or 4ku/l under age 2, 7mm or 7ku/l over the age of 2. 

Encourage early introduction of peanut (do peanut test at the same time, if you are going to test), as per EAT study. 

Children referred to dieticians have half the rate of accidental reactions! Referral to dietician if multiple food allergies, or nutritional concerns, or difficulty following ladder; or if severe allergy. 

1/3 of children grow out of their egg allergy by age 3, 2/3 by age 6.  Predictors of tolerance are ability to have baked egg, mild reactions only, isolated egg allergy, IgE level (and presumably SPT but no mentioned), and possibly isolated component sensitization.

Since most children do grow out of this allergy, step by step, cautious reintroduction should be encouraged from 12 months of age, or 6 months after the last reaction.  This can be safely done at home unless:

  • history of severe reaction
  • severe or poorly controlled asthma

Mild asthma, and reaction to trace amount (or contact only) are relative indications.

Egg “ladder” for step by step reintroduction simply baked egg (eg sponge cake), followed by less well cooked egg (French toast), followed by raw or nearly raw (mayonnaise). 

Where stage 1 achieved but difficultly moving further, regular ingestion should promote tolerance

Although can be frightening to challenge at home, prolonged total exclusion more likely to lead to persistent allergy, and of course increases dietary plus social exclusion. 

If there is a reaction at any stage, the previously tolerated diet should be continued and further escalation considered after 3-6 months.

Remember vaccines – MMR made using egg but no identifiable egg protein remains so egg allergy not given as possible contraindication.  Out of the scheduled vaccines, only influenza vaccines is a potential issue, and even then nasal flu vaccine (or low egg or egg free injectable version) can be given with standard precautions unless anaphylaxis to egg requiring intensive care. Just specialist travel vaccines eg Yellow fever that might be an issue. For latter, should be “referred to specialist with access to designated YF vaccination centre” (3 in Lanarkshire, including Monklands hospital travel clinic and Calderlea centre at Alison Lea!).  No mention of JE, TBE??

[BSACI guidance 2021]