Perhaps you have experienced unexplained skin rashes (known as hives) or vomiting or diarrhea? Does your child refuse to eat a certain food, or complain that it makes his “tongue hurt”? These could be signs of a food allergy, and should be taken seriously.

It is common for the symptoms of food allergy to vary by individual – and from reaction to reaction in the same person. Not everyone will get all the symptoms, which range greatly in severity from mild to severe (and even fatal): your throat may feel tight on one exposure to your allergen or you may get itchy hives on your skin and vomiting with the next.

The Range of Symptoms

-Tingling in the mouth
-Swelling of the tongue and throat / feeling of throat tightness
-Itchy skin, hives or skin redness
-Abdominal cramps
-Vomiting or diarrhea
-Breathing difficulty, wheezing
-Faintness due to a sudden drop in blood pressure

Symptoms reviewed by Dr. Susan Waserman

Anaphylaxis

Anaphylaxis is the severe form of allergic reaction. It involves one or more of the body’s symptoms; for example, the gastrointestinal tract, the respiratory tract, the skin and the cardiovascular system. A person experiencing anaphylaxis often has difficulty breathing, and the person could lose consciousness. Anaphylaxis puts a person at risk of death.

Anaphylactic reactions can come on quickly, and it’s impossible to know when a reaction will become severe. It’s important that people with food allergies are prepared for a reaction by always carrying an epinephrine auto-injector (either EpiPen or Auvi-Q/Allerject).

Experts recommend using epinephrine early if a person known to be at risk of anaphylaxis begins to show signs of allergy symptoms – don’t wait until the symptoms worsen, as it may become to difficult put a halt to the reaction once it’s in progress.

The study, published in the European journal Allergy, found that in a group of 141 selected children with peanut or cashew allergy, the cashew group was more likely to experience shortness of breath, wheezing or cardiovascular symptoms during reaction than the peanut group. (This was despite the fact that a majority of the children with peanut allergy also had asthma.)

The Study and Findings

In 2007, researchers paired 47 children whose worst ever allergic reaction was to cashews with 94 children whose worst ever allergic reaction was to peanuts. Two children with peanut allergy were matched to every one child with cashew allergy and comparison criteria also included sex,

The study revealed that 22 per cent of children with cashew allergies experienced shortness of breath and/or collapse compared to 1 per cent of children with peanut allergies.

Also, while oral antihistamines were most frequently used as treatment by both groups, epinephrine was administered much more often in the children with cashew allergies. (Thirteen per cent of the cashew allergic compared to 1 per cent of the peanut allergic.)

What This Means

This study is important because: it shows the severity of tree nut allergies in general, the cashew specifically and raises the issue of the need for better public awareness.

The researchers advised fellow health-care professionals that “the diagnosis of cashew nut allergy increases the odds of a severe reaction and requiring intramuscular adrenaline and should also be considered in the risk assessment.”

As well in terms of managing the allergy, they noted that cashew can be a hidden food. “Cashew nuts present a considerable hazard, being hidden in a wide variety of commonly ingested foods, such as Asian meals, sweets, ice cream, cakes, chocolates and they are increasingly used in commercially prepared pesto sauce instead of pine nuts,” they wrote.

awareness in the public of the seriousness of tree nut allergy is not as high as awareness of peanut allergy.   it places importance on tree nut allergies despite the fact that peanut allergies tend to get more attention in scientific studies and the media. While it is now very common to see “Peanut-Free” logos on snack foods and candy bars, it is rare to see the same for tree nuts.

Further, we now suggest that the diagnosis of cashew nut allergy increases the odds of a severe reaction and requiring intramuscular adrenaline and should also be considered in the risk assessment.

It has been suggested that cashew avoidance is easier than peanut avoidance (10, 14); nonetheless it is not straightforward. A recent study showed that 10/37 (27%) of nut-allergic children were unable to correctly identify the type of nut to which they were allergic (15). Cashew nuts are commonly sold as the whole nut alone, or packaged with other nut types. Cashew nuts present a considerable hazard, being hidden in a wide variety of commonly ingested foods, such as Asian meals, sweets, ice cream, cakes, chocolates and they are increasingly used in commercially prepared pesto sauce instead of pine nuts. Specific information on how to achieve nut avoidance should always be provided.

The study found that cashew allergies, specifically, are on the rise and are no longer uncommon. Furthermore, it can be just as challenging to avoid cashews as it is to avoid peanuts since cashews can hide in desserts, ice creams, trail mixes and other unexpected places.

More on this study, click here.

A major study in the United States recently found that cases of tree nut allergy in children increased significantly in a decade, from 0.2 per cent in 1997 to 1.1 per cent in 1998. The same study found that more than 3 million Americans now have a peanut or nut allergy.

In Canada, recent research has shown 1.59 % of children have an allergy to tree nuts, and 1 per cent of adults live with the allergy.

In fact, food allergy in general is on the rise in North America and other developed countries. In Canada, an estimated 7.5 per cent of people have food allergies, representing more than 2.5 million people. In the United States it’s estimated that 12 million Americans (or just under 4 per cent of the population) have food allergies.

Here are the rates of some of the major allergens in Canada and the U.S.

CANADA

Source: Surveying Canadians to Assess the Prevalence of Common Food Allergies and Attitudes towards Food Labelling and Risk (SCAAALAR) study. Published in the Journal of Allergy and Clinical Immunology, June 2010.

UNITED STATES

Peanut, Tree Nut or both:
Children -  2.1 %
Adults – 1.3 %

Source: US prevalence of self-reported peanut, tree nut, and sesame allergy: 11-year follow-up. Published in the Journal of Allergy and Clinical Immunology, June 2010.

1. Refined Oil: When a peanut or nut oil is refined, the chances of the proteins of that food being in the oil are low. While pure refined peanut oil does exist, it is always safer to avoid peanut oil completely since there is no definitive way to tell how much protein is in that oil.

However, as Dr. Antony Ham Pong states, “if a peanut allergic person accidentally eats a food with refined peanut oil, the chances of having an allergic reaction are low because even there is peanut protein in there, it will likely be in very small amounts.”

2. Unrefined Oil: Peanut and nut oils that are cold-pressed,” “unprocessed,” “expelled,” “extruded”) peanut and nut oils are unsafe for peanut and nut allergic individuals. These are much more likely to contain peanut and nut proteins.

3. Where Peanut Oil is Found: It is also important to remember that peanut and nut oils are found in some cosmetics and body-care products. Pay specific attention to lip balms, lipsticks and lip glosses (some are even peanut-butter-flavored!) since those are coming in direct contact with your mouth.

In restaurants, be sure to  ask waiters specifically about the oil used in deep-frying or in sauces; sometimes it is peanut oil.

Sources include: Dr. Antony Ham Pong, allergist

When someone with a tree nut allergy ingests their allergen, even a trace amount, that person is at risk of a severe allergic reaction, called anaphylaxis. An anaphylactic reaction includes more than one of the body’s systems, such as the respiratory tract, gastrointestinal tract, the skin and cardiovascular symptom.

Symptoms of an allergic reaction include tingling in the mouth, swelling of the tongue and throat, itchy skin or hives, difficulty breathing, abdominal cramping and vomiting. In a severe anaphylactic reaction, a person may experience a drop of blood pressure, loss of consciousness and even cardiac arrest and death.

One of the issues in managing tree nut allergies is that reaction symptoms can vary greatly. A person may have minor symptoms on one occasion, but anaphylaxis on a next exposure.

Because tree nut allergy reactions can be severe, it is important that a person with this allergy carry an epinephrine auto-injector (EpiPen or Twinject) with them at all times. Research has shown that a small number of people (about 9 per cent) may outgrow their tree nut allergies.

Prevalence

In Canada, 2009 statistics show that 1.14 per cent of the population is allergic to tree nuts, while in the United States 1.1 per cent of children have the allergy and 0.5 per cent of adults. Tree nut allergy is on the rise: the 2008 telephone survey in the U.S. that found 1.1 per cent of children are allergic to nuts, compare that to just 0.2 per cent of children reported as allergic to nuts in 1997.

More on Tree Nut Allergy Statistics

Next Page: What is a Tree Nut?