Tree Nut Free

A tree nut allergy is a hypersensitivity to dietary substances from tree nuts and edible tree seeds causing an overreaction of the immune system which may lead to severe physical symptoms. Tree nuts include, but are not limited to, almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, shea nuts and walnuts.Total avoidance is complicated because the declaration of the presence of trace amounts of allergens in foods is not mandatory in any country, with the exception of Brazil.

Tree nut allergies are distinct from peanut allergy, as peanuts are legumes, whereas a tree nut is a hard-shelled nut. Subjects allergic to tree nut can experience asthma, skin rashes, itchy throat, swollen eyes. The most severe reaction can lead to anaphylaxis. 

The raw nut protein usually causes a more severe reaction than the oil, and extra roasting or processing can reduce the allergic reaction.

This allergy tends to be lifelong; studies have shown that only about 9% of children outgrow their tree nut allergy.

Cause
People with tree nut allergy are seldom allergic to just one type of nut,[and are therefore usually advised to avoid all tree nuts, even though an individual may not be allergic to the nuts of all species of trees.

Someone allergic to walnuts or pecans may not have an allergy to cashews or pistachios, because the two groups are only distantly related and do not necessarily share related allergenic proteins.

Diagnosis
An allergy test or food challenge may be performed at an allergy clinic to determine the exact allergens.

Cross-reactivity
People with clinically confirmed tree nut allergy to one type of tree nut may have cross-reactivity to other tree nut species and also to peanuts, which are not nuts but rather part of the legume family. The cause is similarity in protein structures. Identifiable allergenic proteins are grouped into families: cupins, prolamins, profilin and others. Tree nuts have proteins in these families, as do peanuts and other legumes. Reviews of human trials report that for a confirmed tree nut allergy, up to one third of people will react to more than one type of tree nut. The cross reactivity among almond, walnut, pecan, hazelnut and Brazil nut is stronger than cross reactivity of these toward cashew or pistachio.Treatment. Strict dietary avoidance of the causal nut(s) remains the mainstay of treatment for nut-allergic individuals. If the food is accidentally ingested and a systemic reaction (anaphylaxis) occurs, then epinephrine should be used. People with potential anaphylaxis are recommended to carry auto-injectors at all times Less severe reaction may be dealt with by taking antihistamines tablet.