IgE mediated food allergy is increasing in Australia. 1 in 10 children at 12 months of age in Australia has a clinical proven food allergy, with egg, cow milk and peanut being among the three most common IgE mediated food allergies. Often young children with food allergy have eczema, and the combination of food allergies and eczema can have a significant impact on the quality of life of parents and their allergic child. Proper diagnosis and management and understanding of the limitations of food allergy testing is paramount.
Severe eczema, particularly in infancy, increases the risk of IgE mediated food allergy. IgE mediated food allergy should be suspected in any children when there is an immediate reaction (usually within 1-2 hours of ingestion) following ingestion of a food, resulting in symptoms/signs involving the cutaneous (urticaria, hives, angioedema, eczema flares), gastrointestinal (vomiting, abdominal pain), respiratory (wheeze, cough, difficulty breathing, hoarse voice), and/or cardiovascular systems (floppy, hypotension).
Either by skin prick testing (SPT) or ssIgE (formerly called RAST testing). Both are testing sensitization (i.e development of IgE antibodies to a food allergen). SPT is easy to perform the results are quickly available and many different allergens can be ordered. ssIgE does involve a blood test, and currently only 4 allergens are currently covered by Medicare.
Panel testing should not be done, and instead specific food allergens should be ordered based on the clinical history. For example, if a child has immediately developed urticaria after drinking cow milk, then SPT/ssIgE to cow milk and soy should be done (as soy is usually the safest alternative). The interpretation of the SPT/ssIgE can sometimes be complex, but some general rules are:
Currently management of IgE mediated food allergies involves avoiding the trigger(s) in question, determining if a modified version of the food protein can be ingested under medical observation (e.g. in those with egg/cow milk allergy, often we can perform baked egg/cow milk challenges under medical observation), repeat SPT/ssIgE to determine if the child potentially has outgrown their allergy (which is then confirmed with a food challenge), and in those deemed at higher risk of anaphylaxis, an adrenaline auto-injector is prescribed. Action plans must also be provided. Desensitisation to food allergens is still under research and still not yet in clinical practice.
If IgE mediated cow’s milk allergy is confirmed (i.e. immediate clinical reaction to cow milk and positive SPT/ssIgE to cow’s milk)
|Reaction severity to cow milk||Age group||Formula/milk alternative|
|Mild-moderate (i.e. skin or GIT reaction only)||< 6 months of age
> 6 months of age
|Extensively hydrolyzed formula*
|Severe (anaphylaxis, i.e respiratory or cardiovascular involvement)||Any age||Amino acid formula***|
* This can be prescribed by a Paediatrician, Paediatric Gastroenterologist or Allergist.
** In older children (> 12 months of age), rice/almond milks may be an alternative but it is important to note this are poor sources of protein and should only be used after discussion with the doctor/dietician.
*** This can only be prescribed by a Paediatric Gastroenterologist or Allergist.
Skin Prick Testing is now available at Offspring. Patients will be required to make an appointment for this service that will be performed under the supervision of an Allergist/Immunologist. Patients will be provided with a written report documenting the results of the test as well as further information sheets about relevant allergen avoidance where appropriate. A report with the results will also be forwarded to the referring doctor. For patients intending to undertake a skin prick test, please do not take antihistamines for at least 5 days prior to your appointment as this will interfere with SPT and therefore this will not be able to be undertaken. Finally, for parents of young children your appointment may take up to 2.5 hours, so please ensure you come prepared.