by Antony Ham Pong,
Ham Pong is a lecturer in the department of pediatrics, University
of Ottawa, consultant, Children's Hospital of Eastern Ontario, and
committee member, Regulatory Review Project 19 (labelling of food
causing severe adverse reactions in Canadians), joint Agriculture
and Health Canada Commitee, Ottawa, Ontario. He also has a private
practice in allergy.
Tree nut allergies are
common potentially life-threatening food allergies. They are often
lifelong. Tree nuts may belong to different food families which
are unrelated to each other and tree nuts are not related to peanut.
Peanut allergic people can often eat tree nuts and tree nut allergic
allergic people can often take peanuts. However, some allergic individuals
may be allergic to both peanut and tree nuts. In addition, you can
be allergic to some but not all tree nuts. Almond seems to cause
the least problems of all common tree nuts.
filbert, hickory nut
Nuts may be found as a hidden, unlabelled part of a food because
of accidental cross-contamination
during manufacturing. Allergic reactions are often caused by eating
unlabelled foods, by not checking food labels properly for presence
of nuts, or from foods which contain hidden unlabelled nuts. Nuts
may be used in many of the foods that people like to eat. The most
common types of foods causing allergic reaction due to nuts are
chocolates, cookies, candies, granola bars, ice cream.
Special occasions such as Easter, Halloween, Christmas and birthday
parties are more dangerous for children with nut allergies because
there is much more likely to be nut containing foods eaten, and
because it is more difficult to supervise children properly. In
addition, usual common sense precautions may be forgotten in the
excitement. At school, allergic reactions to nuts can happen if
children share foods or a parent sends foods containing nuts, e.g.,
muffins, as a treat for the whole class.
What may contain
- chocolate, candies, cookies, desserts, sweets, almond paste, donuts,
sundaes, cereal, milkshakes, granola bars, trail mixes, pesto sauce,
European chocolates, muesli
- suntan lotion, shampoo, nut shells, bath oils
- popcorn and speciality cheese spreads
- gianduja (chocolate and chopped toasted nuts)
- speciality coffees, liqueurs
- small animal food e.g., hamster, gerbil
What contains walnut
(grenoble, noix royal) / pecan (pecan)?
- pecan pie, walnut containing muffins
- Crosse & Blackwell Worchestershire sauce
- AIM herbal fiber blend, pesto sauce, pralines, walnut oil, "Turtles"
What contains hazelnut
/ filbert (noisette)?
- Nutella, nougat, Toblerone chocolate bars, hazlenut liqueur, Frangelico
liqueur, hazelnut coffee
What contains pistachio
(pistache) / cashew (cajou)?
- cashew butter, pistachio ice cream, chicken with cashews
What contains almonds
- marzipan, almond mocha, almond paste, almond guy ding, trout almondine,
pure almond extract (artificial is okay), amaretto
What can happen
during an allergic reaction to nuts?
An allergic reaction to a food usually begins within minutes
but may be delayed for 2-4 hours and usually lasts less than one
day. The more severe the allergy, the smaller the amount required
to cause a reaction. Typical immediate allergic reactions to foods
include hives or blotching around the mouth which may spread to
the rest of the body, immediate runny nose, sneezing and itchy water
eyes, coughing, choking or gagging, wheezing and trouble breathing,
and cramps, vomiting and diarrhea. The allergic reaction can stop
at any stage, or may progress to anaphylaxis and death. Anaphylaxis
is a severe allergic reaction which involves several parts of the
body and can lead to death.
A food does not have
to be eaten to cause an allergic reaction but eating it does cause
greater amounts to get into the body and usually causes the most
severe reactions. Hives can occur on skin contract with an allergenic
food. If the food goes into the wet surfaces, e.g., through a cut
in the skin, or at the lips (e.g., being kissed by someone who has
eaten nuts), or in the eye, severe reactions can occur.
Do I have to avoid
You do not have to avoid other nuts if you are only allergic to
one family of nuts. See above chart of nut families.
How do I treat
an allergic reaction on eating nuts?
Anyone with severe nut allergy should use their EpiPen immediately when they begin to have reactions to eating nut
accidentally, even if the reaction initially is minor. This
is important to prevent anaphylaxis, the most severe form of an
allergic reaction. People who delay treatment with Epinephrine are
more likely to die. EpiPen therefore should always be immediately
close at hand, i.e., not in the locker, in the car, in the hotel
room, or next door. A person with asthma is more likely to have
a fatal food reaction. An allergic reaction, especially anaphylaxis,
can recur 4-8 hours after initial treatment. It is important to
go to the hospital immediately for further treatment and to be observed
for several hours after.
If an allergic reaction to nuts begins, use EpiPen immediately
as soon as any allergy symptoms develop! Take patient to hospital
immediately, preferably by ambulance.
I have eaten foods
labelled "may contain nuts" without any problems. Should
I still avoid them if I am allergic to nuts?
Definitely avoid them! Companies are allowed to use "may
contain nuts" if they cannot guarantee that a food they are
producing is free of nuts, usually because nuts are being used in
the same machines for other foods. A company that makes similar
foods with and without nuts, may have difficulty cleaning the machines
in between making the different foods, or packages may be mislabelled.
These food manufacturing machines were designed many years ago,
and were never designed to be taken apart and cleaned properly.
In addition, some of these machines cannot be cleaned with water.
Therefore it is quite likely that when a food with nuts is put through
the machine, traces of nuts remain on the machine. The first batches
of foods made without nuts that go through the same machine will
likely contain trace of nuts. Batches of foods done much later are
less likely to contain traces of nuts but you cannot be sure which
batch of food you are eating. Therefore they should be avoided.
This cross-contamination is most likely to occur with cookies, candies,
cereals, chocolate, ice cream, dried soups and nut butters.
What about seeds,
tropical oils, exotic nuts?
Foods such as water chestnut, pine nut (pignolia or pinyon nuts),
coconut, nutmeg do not need to be avoided by nut allergic people
unless they are also allergic to these foods. However, allergies
to these foods are uncommon. Palm oil and tropical oils do not need
to be avoided. Seeds, e.g., sesame, sunflower, poppy, mustard, safflower,
canola, do not need to be avoided unless you are allergic to these
I have had only
a mild reaction to nuts in the past, and have never had breathing
difficulties. Why do I need an EpiPen?
Nut allergy is usually potentially life-threatening and
life-long. Even if mild allergic reactions have occurred in the
past, severe reactions can still occur with the same amount of food,
i.e., the allergy can worsen without warning. Do not also expect
that you will have the same amount of time or warning before the
reaction occurs as in the past. Therefore EpiPen should be available
at all times.
What foods are
more likely to contain undeclared nuts?
Chocolate and mint ice cream are most likely to contain undeclared
nuts since leftover ice cream can be added to these without changing
the flavour. See list above (what may contain nuts). European chocolates
are allowed to be made with leftover chocolate which may contain
nuts and may not be declared.
How can I tell
if my nut allergy is "anaphylactic"?
Many tree nut allergies have a potential for anaphylactic reactions.
Anaphylaxis is the most severe form of an allergic reaction as described
below. Even a mild food allergy can cause anaphylaxis if enough
is eaten. Once you have been prescribed an EpiPen, it means that
you have the potential for life-threatening or are "anaphylactic".
Whether anaphylaxis will occur depends on how allergic a person
is, how much of the food is eaten, how early treatment is started,
whether EpiPen is given, and whether the person is having an asthma
attack at the time or has chronic asthma.
Are nut oils safe?
Most tree nut oils probably contain enough allergenic protein to
cause allergic reactions. These are cold pressed (unprocessed, extruded
or expelled) oils and are not safe for nut allergic people.
EXAMPLES OF HOW ACCIDENTS WITH FOOD CAN HAPPEN
* These have resulted in deaths
- Eating unlabelled
foods*. If in doubt, don't.
- Unpackaged foods,
e.g., a cookie jar, may contain traces of nuts from previous nut
containing cookies. Another cookie taken from that jar may contain
traces of nuts on it. Bulk foods, and buffet meal may also be
dangerous because of cross contamination. Free cookies at stores.
during preparation, e.g., a cutting board used to cut 2 foods
such as chicken and fish -- the chicken served to a fish allergic
person or the same board or knife to slice or grind nuts. Using
the same oil to fry different foods, or the same batter for different
foods, or the same frying utensils for different foods without
washing in between can all cause cross contamination.
- Grinding specialty
nut flavoured coffees in a coffee grinder. Baking muffins with
and without nuts if leftover batter is used for the other muffins
or if the baking pans are not properly cleaned. Contamination
during serving, e.g., sauces mixed by spillage; the same scoop
used to take scoops of different ice creams, some of which may
contain nuts; a knife used to cut a nut containing dessert and
used to cut another dessert.
- Relying on someone
who does not know but who tells you the food is safe e.g., another
child, or someone who did not prepare the food e.g., waiter or
salesclerk, airline steward.
- Trying a food to see
if you are "still allergic" especially with anaphylactic
- Tasting a food carefully
to see if it is safe or is not dangerous.*
- A change in the way
a usual food is made, e.g.., a change in the ingredient list without
any obvious change on looking at the container. A new chef at
a restaurant may change the recipe and add a "secret ingredient".*
- Candy machines may
have different foods at different times and candies may be contaminated
with traces of nuts if there were nuts in the dispensing machine
- Be aware of unusual
sources of allergenic foods. See list of "what may contain
- Non-food sources of
nuts e.g., bags made with nut shells, interactive museum displays
made with nut shells, small animal food e.g., hamsters, gerbils.
For further information, we strongly recommend you become a member
- AAIA, Box 100, Toronto, Ontario M9W 5K9, Toll-free call 1-800-611-7011.
Email firstname.lastname@example.org. Web site: www.aaia.ca.
- Food Allergy Network, 10400 Eaton Place Suite 107, Fairfax, VA,
USA 22030-2208. Toll-free call 1-800-929-4040. Web site: www.foodallergy.org.
Anaphylaxis is the most
severe form of allergic reaction. It may occur with a food, drug
or insect sting. Evan a trace amount of food can cause a severe
allergic reaction. Anaphylaxis is an allergic reaction occurring
over many parts of the body and can lead to death. Anaphylaxis can
occur minutes after taking a food, or may occur several hours later.
Death can also occur immediately or be delayed for several hours.
How an allergic reactions begins does not necessarily tell you that
anaphylaxis will or will not occur.
Features of anaphylaxis are:
- swelling of the upper
airway causing trouble breathing, croup like symptoms, and suffocation
- swelling of the lips
and tongue with trouble swallowing and breathing
- runny nose, nasal
congestion, sneezing, itchy watery eyes
- skin eruptions such
as hives or redness. Itchy anywhere
- constriction of the
lower airways with wheezing, asthma and cough.
- dizziness and feeling
like dying. Low blood pressure, shock.
- nausea, cramps, diarrhea
of Use: The information
on this site does not constitute medical advice and is for your
general information only. We cannot be held responsible for anything
you could possibly do or say because of information on this site.
Consult your family physician or allergist for specific questions