Peanut component testing is a new method of allergy testing to help diagnose peanut allergy. Approximately 1% of school aged children in North America are diagnosed with peanut allergy and this number is on the rise. This can be a lifelong allergy condition with only 20% of children diagnosed with peanut allergy outgrowing it. It is the most common food related cause of fatal allergic reactions to Western countries. Peanut allergy is usually diagnosed by an allergy doctor via allergy skin testing or blood testing. However sensitization does not always correlate with allergic symptoms in a percentage of patients. This may be true because crude natural peanut extracts contain allergic and non-allergic components and some of these components may cross reacts with other allergens.
There are over 13 allergenic components identified in peanuts. The most important markers that have been identified are Ara h 1,2,3,6,8 and 9. Ara h 1,2, and 3 are seed storage proteins and sensitization to them is associated with a high risk of a systemic allergic reaction (anaphylaxis). Ara h 2 is a more important predictor of clinical peanut allergy than Ara h 1 and 3, and is most often associated with severe allergic reactions.
Ara h 8 is associated with a low risk of systemic reactions and a moderate risk of oral allergy syndrome. Ara h 8 cross reacts with Birch pollen. Ara h 9 sensitization can result in systemic reactions, however the amount of Ara h 9 in peanuts is generally low. Ara h 9 is cross reactive to fruits with pits, i.e. peaches.
The peanut component testing tests for IgE allergy antibodies to peanut allergens Ara h 1,2,3,8 and 9. Identifying sensitization can assist in assessing allergic reactions.
In conclusion if you have had the peanut component testing done, reactivity to Ara h 1,2, or 3 is associated with a high risk of a systemic reaction, including anaphylaxis. Reactivity to Ara h 9 is associated to a variable risk for a systemic reaction.
Reactivity to Ara h 8 and non reactivity to Ara h 1,2,3, and 9 indicates a low risk of a systemic allergic reaction. Patients with only Ara h 8 sensitization may consider taking an oral food challenge at an allergists or allergy doctors office.
For more information on peanut allergy please read.