- General points – The most common food allergens for children are milk, egg, peanut, tree nuts, soy, fish, shellfish, wheat, kiwi fruit and sesame
- Further guidance for milk and egg allergy are given below as these are relatively common food allergies with distinctive natural histories
- Take an allergy-focused history, noting -
- Speed of onset of symptoms following contact with suspected food (reactions after 2 hours extremely unlikely to be IgE mediated)
- Which food(s) ingested, and how much of that food caused the reaction?
- Symptoms and signs in relation to the food exposure, always note
severity – particularly whether airway or circulation involved (anaphylaxis). Often a dose – response relationship, but can be unpredictable, subsequent reactions not always worse
- Whether reaction has been reproducible (has child had that food since with no reaction – if they have they are not allergic to that food)
- Feeding history, including whether breast or formula fed / weaning and any timings of feed changes vs symptoms
- Allergic co-morbidities (esp. asthma, eczema, rhinitis) present?
- Family history of current / past atopy –
But family history of food allergy is not an indication for referral
Based on history, decide which type of allergy you suspect –
IgE – mediated or non-IgE mediated
- IgE-mediated symptomshave acute onset (usually minutes to not more than 2 - 4hrs post exposure) and include one or a combination of urticaria, angioedema, rhino-conjunctivitis, wheeze, stridor, repetitive and copious vomiting, collapse
Any airway involvement or circulatory compromise = anaphylaxis even if no rash
Refer any child who has had a significant IgE-mediated reaction to a small amount of food, or anaphylaxis
- Non-IgE-mediated symptomshave delayed/non-acute onset and include exacerbation of atopic eczema, worsening of gastro – oesophageal reflux or reproducible abdominal upset (vomiting, loose stools) after that food
- Reassure parents that not a dangerous allergy
- Try a trial of elimination of suspected allergen for 2-4 weeks
- If child does not improve, allergy unlikely; treat for the reflux / constipation / eczema bearing in mind commonality of these conditions without food allergy being presen, and re-introduce the food
- For a diagnosis and treatment plan specific to non – IgE milk allergy, see section on milk below.
- If child does improve then worsens on re-introduction of food, make the diagnosis and advise avoidance. Paediatric dietitian referral recommended if doubt about nutritional adequacies of diet or timings of food re-introduction
- Consultant – led Paediatric allergy clinic referral if child has faltering growth on serial weights (rare) or multiple foods responsible on trial elimination / re-introduction
Differential diagnosis of food allergy
IgE – mediated
Chronic spontaneous urticaria – itchy urticarial rash, not always related to food, but acidic foods can also flare this condition. Some 10-40% have angioedema too. See separate section.
Non IgE – mediated
Chronic diarrhoea (consider Toddler Diarrhoea)
Lactose intolerance (see separate section)
Eczema, not food – related
Guideline updated by Simon Bedwani, Consultant Paediatrician, Royal Cornwall Hospital, November 2018.
Review Date 14/08/2019
Next Review Date 14/08/2020
GP Sifter Dr Rebecca Harling
Version No. 2.1