Tree nut allergy, a hypersensitivity to
dietary substances from tree nuts causing an overreaction of the immune
system, 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, pine nuts, and walnuts.
Tree nut allergy is distinct from peanut allergy, as peanuts are legumes, whereas
a tree nut is a hard-shelled fruit. Description
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 not biological related and do not
necessarily share related allergenic proteins. The severity of the allergy
varies from person to person, and exposure can increase sensitization. For
those with a milder form of the allergy, a reaction which makes the throat feel
like cotton may occur . The raw nut protein usually causes a more severe
reaction than the oil, and extra roasting or processing can reduce the
allergic reaction. Those diagnosed with anaphylaxis will have a more immediate
mast cell reaction and be required to avoid all exposure to any
allergen-containing products or byproducts, regardless of processing, as
they are prone to even greater sensitivity. An allergy test or food
challenge may be performed at an allergy clinic to determine the exact allergens.
New immunotherapy treatments are being developed for tree nut allergy.
This allergy tends to be lifelong; recent studies have shown that only
about 9% of children outgrow their tree nut allergy.
Hazelnut has been used as a model tree nut in the study of tree nut allergies.
Prevention and treatment In the United States, the federal Food
Allergen Labeling and Consumer Protection Act requires that any
packaged food product that contains tree nuts as an ingredient must list the
specific tree nut on the label. Foods that almost always contain tree nuts
include pesto, marzipan, Nutella, baklava, pralines, nougat, gianduja, and
turrón. Other common foods that may contain tree nuts include cereals,
crackers, cookies, baked goods, candy, chocolates, energy/granola bars,
flavored coffee, frozen desserts, marinades, barbecue sauces, and some
cold cuts, such as mortadella. Tree nut oils are also sometimes used in lotions
and soaps. Asian and African restaurants, ice cream parlors, and
bakeries are considered high-risk for people with tree nut allergy due to the
common use of nuts and the possibility of cross contamination.
There has been a single documented case of pink peppercorns causing an allergic
reaction in those with nut allergies. Pink peppercorn is not a true pepper,
but dried roasted berries derived from Schinus terebinthifolius, a flowering
plant in the family Anacardiaceae, native to South America. Common names
include Brazilian Pepper, Rose Pepper and Christmasberry. Pink peppercorns are
used as a spice to add a mild pepper-like taste to foods. It may
potentially cause an irritating skin effect and has been associated with
atopic dermatitis in canines. Interestingly, S. terebinthifolius is a
member of the family Anacardiaceae, which include plants in the genera
Anacardium and Pistacia. No allergens from this plant have been characterized
but there is potential for cross-reactivity among different members
of the Anacardiaceae family. Treatment usually involves an exclusion
diet and vigilant avoidance of foods that may be contaminated with tree nuts,
nut particles, or oils. The most severe nut allergy reaction is anaphylaxis, an
emergency requiring immediate attention and treatment with epinephrine.
Tree nut alternatives Since many people with tree nut
allergies also have peanut allergies, and peanut butter is a popular
derivative of peanuts and widely used product, especially in the United
States, many schools offer peanut-free menu options or implement entirely
nut-free policies. For instance, sunflower seed butter can provide an
alternative in schools where peanut butter and peanuts have been banned.
However, a small number of people with tree nut and/or peanut allergies may
also be allergic to sunflower seed butter. According to one study a person
with a known peanut allergy suffered an acute reaction to a “nut-free” butter
containing sunflower seeds. From a nutritional perspective,
sunflower butter contains almost four times as much vitamin E as peanut
butter, and about twice as much iron, magnesium, phosphorus and zinc. Peanut
butter contains higher levels of protein and slightly less sugar and fat.
Sunflower butter, or sunflower seed butter, is a food paste made from the
oil of sunflower seeds. Leading brands in the United States include SunButter
and Trader Joe’s sunflower seed butter. See also
Allergy List of allergies
Anaphylaxis Food allergy
Asthma Peanut allergy
External links Tree nut allergy at Food Allergy
Initiative “Are Nut Bans Promoting Hysteria?” by
Tana Parker-Pope at The New York Times Is Peanut Allergy Related to Tree Nut
Allergies? at PeanutAllergy.com ^ Basic Pathology – Robbins et al – 9th