Peanut Allergy Treatment for Children

Diagnosis and Testing Options for Peanut Allergy

Peanut, tree nut, and seed allergy are some of the most common food allergies in both children and adults. These allergies tend to cause severe reactions and usually persist over time.

The prevalence of peanut allergy is variable worldwide. The prevalence is approximately 1-2%. Peanut allergy is rare in Asia.

Nine major and minor allergenic proteins in peanut (Arachis Hypogaea), designated Ara h 1 to 9, have been identified and are responsible for IgE mediated peanut allergy reactions. Ara h 1, 2, 3, 4, 6, and 7 are seed storage proteins and are responsible for causing systemic allergy reactions. Seed storage proteins are heat stable thus do not denature on cooking. High heat roasting increases protein stability and allergenicity.

Ara h 5, 8 and 9 are proteins that are associated with pollen-food allergy syndrome PFS (oral allergy syndrome OAS). Ara h 8 is a Bet v 1 (birch tree pollen) and cross reacts with birch tree pollen allergy causing hay fever.

The timing of introduction of a food probably influences the development of allergy versus tolerance. Peanut allergy has more than doubled in young children in countries where delayed introduction of peanut until at least 3 years of age was recommended. The rate of peanut allergy is low in countries where Peanuts are introduced at a younger age.

Evidence suggests that maternal avoidance of allergenic foods during pregnancy and lactation does not reduce the risk of atopic disease in children.

Infants with severe atopic dermatitis or hen’s egg allergy are at increased risk of developing peanut allergy. Peanut, tree nuts and seeds allergies are typically lifelong although a small percentage of patients may outgrow these allergies.

Reactions localised to mouth and throat can occur upon ingestion of peanut and certain tree nuts in individuals who are sensitised to plant allergens e.g. Bet v1 (Birch pollen allergen). These reactions are termed as oral allergy syndrome (OAS) or pollen food syndrome (PFS). Symptoms are usually observed with eating raw peanuts because the causative allergens are rapidly inactivated by digestion and cooking. Children with primary allergy to Bet v1 PR 10 protein (Ara h8), may be able to eat roasted peanuts.

Diagnosis: Clinical history supported by the following tests. Assessments should be undertaken every 2-3 years.

IgE mediated allergy
Skin Prick Test
Blood test- Total IgE and IgE to peanut
Component peanut protein test

Management:
Peanut-free diet
Peanut immunotherapy – PALFORZIA