Hazelnut allergy can cause severe systemic reactions, tree nuts are common causes of food allergy. In the United States, the prevalence of nut allergy has been reported between 1.1-1.3%. In Europe, the most common food allergy sensitization was to hazelnuts in adults, making hazelnut allergy a serious problem. Hazelnut allergy can have a considerable negative impact on the quality of life. It is crucial to make an accurate diagnosis and prevent unnecessary elimination diets. A recent study shoed that 9% of patients outgrow their tree nut allergy.
Diagnosing hazelnut allergy can be done with allergy IgE blood tests and skin prick tests, the gold standard test although is the food challenge. There are cutoff values for cow’s milk, egg and peanut, but there is limited information about hazelnut allergy. Component testing (IgE blood testing) for hazelnut allergy has been elucidated with Cor a 1, Cor a 8, Cor a 9, Cor a 14 and Bet v 1.
Many patients can be diagnosed with hazelnut allergy if their skin test is positive or their lab testing shows an elevated IgE to hazelnut. Some of these patients won’t actually be allergic to hazelnut though. A recent study published in the March/April 2016 issue of The Journal of Allergy and Clinical Immunology In Practice, helped better define what values truly constitute hazelnut allergy. They found the optimal cutoff levels that predicted the highest sensitivity and specificity for hazelnut allergy IgE testing was 3.15 kU/L. For the allergy skin test, the cutoff wheal diameter was 7.5 millimeters. Among the more specialized allergy blood component testing, only Cor a 14 discriminated between reactive and nonreactive children. These values are just suggested cutoff values and every patients care needs to be individualized. Many patients with lower values can still be allergic and higher values may not actually be allergic. The component testing for Hazelnut (Cor a 14) will be helpful in elucidating true allergy, the cutoff value for that with 95% probability was determined to be 1.0 kU/L.
We have discussed component testing in the past Peanut Component testing and also for eggs and milk, Milk and Egg Component Testing. The Cor a 14 component test in addition to the allergy skin test and IgE test can all be used together to properly diagnose hazelnut allergy, thus avoiding unnecessary elimination diets and potentially positive food oral challenges to hazelnut.
Your allergist would be the best physician to speak to regarding your food allergies. If you are concerned regarding any food allergies, go see an allergy doctor who can best properly diagnose you.