There are many kinds of tree nuts: almonds, cashews, and walnuts are well-known examples.

Tree nut allergies are a common type of food allergy for both children and adults. A tree nut allergy, like any allergy, is when your immune system identifies something you eat or come in contact with, as harmful. When you eat or even touch tree nuts, the proteins cause your immune system to respond and release histamines, which then cause your allergic symptoms. An allergy to tree nuts could result in anaphylaxis—a life-threatening allergic reaction.

Unfortunately, a tree nut allergy usually lasts a lifetime—fewer than 10% of people outgrow it. Some people who have previously had severe reactions to tree nuts will eventually outgrow their tree nut allergy. So, the severity of your reaction doesn’t necessarily mean you won’t outgrow the allergy.