Abstract
The incidence of food allergy, and particularly peanut allergy, has increased substantially in Australia over the past decade. A thorough clinical history and specific testing should be conducted to identify the allergen. Allergen avoidance and education are currently the mainstays of treatment.
Key Points
- More than one-third of children with IgE-mediated food allergy will react on their first known ingestion of a food.
- Cow’s milk, egg, peanut, tree nuts, fish, shellfish, soy and wheat cause more than 90% of food allergies in children.
- Exclusion diets should only be undertaken with specialist advice because they may inadvertently worsen, rather than aid, the child’s situation.
- Foods already tolerated in the child’s diet should not be removed if a skin prick test or serum-specific immunoglobulin E to that food is positive but there are no clinical signs of allergy to that food.
- New evidence suggests that early introduction and regular ingestion of certain allergenic foods significantly reduces the risk of developing food allergy.
- There is currently no scientific evidence to suggest anaphylaxis can occur from skin contact with an allergen.
Picture credit: © Astier/BSIP/SPL
Food allergy is an increasingly common problem that affects about one in 10 babies (up to 12 months old) in Australia.1 Furthermore, the incidence of peanut allergy has undergone a 100% increase over the past 10 years.2,3
The mainstays of treatment of children with immunoglobulin E (IgE)-mediated food allergy are correct allergen identification and avoidance, education about management of an acute reaction and optimal treatment of other atopic conditions, particularly asthma. Future treatments may include oral desensitisation. This article discusses IgE-mediated food allergy in children and strategies for its management.
Defining food allergy
A food allergy is an adverse reaction to a generally harmless substance within a food (usually a protein) that is mediated by the immune system. There are essentially three main types of food allergy: IgE-mediated, nonIgE-mediated, and mixed IgE- and nonIgE-mediated. Food may also cause symptoms through nonimmune mechanisms such as lactase deficiency, but this is not defined as a food allergy.
Why is food allergy increasing?
The two main factors that influence the development of allergies are:
- genetics
- the environment.
It seems unlikely that the genetic make-up of humans would have changed significantly in the past 10 to 15 years, so genetic changes do not account for the increase in childhood allergy over this time.
Although there are several theories that have been studied in relation to the increase in food allergy, the hygiene hypothesis is one of the most commonly cited. However, it seems unlikely that a single factor would account for the complexities of these diseases.