ORAL ALLERGY SYNDROME
What is an Oral Allergy Syndrome?
Oral allergy syndrome is an allergic (immunologic) reaction to certain proteins in a
variety of fruits, vegetables and nuts, which develops in some people with pollen
allergies. It is referred to as an oral allergy syndrome because it usually affects the
mouth and throat.
These reactions are not related to pesticides or metals.
Who is affected and what pollens are involved ?
Oral allergy syndrome is nearly always preceded by hay fever and tends to occur most
often in older children and adults. It is usually associated with birch-pollen allergies
but it can also affect people with allergies to the pollens of grass, ragweed (more common
in North America) and mugwort (more common in Europe). These reactions can occur at any
time of year, but are often worse during the pollen season involved.
What are the symptoms and when do they occur ?
Symptoms may include itching and burning of the lips, mouth and throat, watery itchy
eyes, runny nose and sneezing. Some individuals report that peeling or touching the
offending foods may result in a rash, itching or swelling where the juice touches the
skin. More serious reactions can include hives and swelling of the mouth, pharynx and
windpipe. In rare cases, severe allergic reactions have been reported such as vomiting and
diarrhea, bronchial asthma, generalized hives and anaphylactic shock. Symptoms usually
develop within minutes of consuming or touching the food, but occasionally occur more than
an hour later.
Are all reactions to fruits and vegetables associated with "Oral Allergy
Syndrome" ?
No. A variety of fruits, vegetables and their juices, including orange, tomato, apple
and grape, sometimes cause skin rashes and diarrhea, especially in young children.
Strawberries occasionally cause hives.
What foods are involved ?
Foods associated with birch, ragweed, grass and mugwort pollen are listed in the
following table. Most reactions are caused by raw foods, since allergenic proteins are
usually destroyed by cooking (i.e., heat labile). The main exceptions to this are celery
and nuts which may cause reactions even after being cooked. Some plant parts, such as the
skin, may be more allergenic than others, however the allergic characteristics of some
fruits seems to decrease during storage. Foods associated with the oral allergy syndrome
which have occasionally been reported to cause anaphylactic reactions include: kiwi,
hazelnut, white potato, celery, parsley, beans, and cumin.
FOODS MOST COMMONLY ASSOCIATED WITH
BIRCH, RAGWEED, GRASS AND MUGWORT POLLENS
Allergies to this type of Pollen |
May also trigger an allergic reaction to these
foods |
Birch |
Fruits
kiwi, apple, pear, plum, prune, peach, nectarine, apricot, cherry
Vegetables
celery, carrot, parsnips, parsley, dill, anise, cumin, coriander, caraway, fennel, potato,
tomato, green pepper, lentils, peas, beans, peanut
Nuts
hazelnut, walnut, almond
Seeds
sunflower |
Ragweed |
Fruits
banana, watermelon, cantaloupe, honeydew
Vegetables
zucchini, cucumber |
Grass |
Fruits
melon, watermelon, tomato, orange, kiwi |
Mugwort |
Fruits
apple, watermelon, melon
Vegetables
celery, carrot |
What can sensitive individuals do to avoid a reaction?
Individuals who are hypersensitive to the foods identified in the above table usually
find that they can consume these foods if they are well cooked, canned or micro waved.
People who develop a rash, itching or swelling when touching or peeling these foods may
prevent this by wearing gloves.
Consultation with a qualified allergist is recommended to determine the cause of
reactions to plant foods, and whether any special precautions are advisable.
Reference :
Zarkadas M, F.M. Scott, J. Salminen, A. Ham Pong. Common Allergenic Foods and Their
Labelling in Canada - A Review. Canadian Journal of Allergy and Clinical Immunology,
1999;4:118-141.
P0154E-00
January 2000
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