• Intense itching;
• Digestive symptoms (e.g. stomach pain, diarrhea, nausea);
• Difficulty swallowing;
• Shortness of breath;
• Nasal congestion or a runny nose;
• Vomiting;
• Itching of the mouth, throat, eyes, skin or any other area.

Tree nut allergies are among the most common causes of anaphylaxis. People with a severe tree nut allergy should be prepared to respond to an anaphylactic reaction at all times.

Tree nut allergy reactions can vary from localized reactions, such as itching and tingling of the mouth and lips, to systemic reactions, including anaphylaxis, to potentially no clinical reaction at all. These reactions may depend on which protein in different tree nuts is causing the reaction.

Tree nuts comprise different proteins; a person with a tree nut allergy could be reacting to one or more of these proteins. Knowing which protein is causing the reaction is important because different proteins can cause different allergic reactions.

Specific IgE blood testing for tree nut components, currently available for hazelnut, walnut, brazil nut, and cashew, helps your healthcare provider identify the specific proteins that cause your reactions. So instead of knowing that you are allergic to a tree nut in general, you can know exactly which protein may trigger the reaction. Testing with allergen components can also help your healthcare provider determine whether an oral food challenge (OFC) test is recommended. An OFC test can be used to help confirm your tree nut allergy or determine whether you have outgrown it.