Tree Nut Allergy

This food allergy is an immune system response linked to tree nuts. It happens when your immune system treats harmless nut proteins as if they're a danger to your body. Almonds, walnuts, pecans and cashews are tree nuts. So are Brazil nuts, hazelnuts, pistachios and pine nuts. A person with this allergy may be allergic to one or more of them. Kids who have a tree nut allergy often don't grow out of it.