Oral Allergy Syndrome
We've got some good news for you: your
allergies may not be as bad as you imagine. If you ever had a fruit or a
vegetable and suffered a mild allergic reaction, you're not necessarily
allergic to it. The culprit might be a pollen allergy if you have it.
This phenomenon of allergic symptoms without an allergy is called oral
allergy syndrome (OAS), sometimes referred to as pollen fruit syndrome,
and you can live quite peacefully with it.
What is OAS?
Oral allergy syndrome occurs in individuals
who already have an allergy to the pollen of certain trees or grasses,
mainly birch, ragweed, and mugwort. The symptoms are mild swelling of
the mouth, face, or throat, or itchiness in the tongue after ingesting
certain fresh fruits, nuts, or vegetables. This happens because your
body recognizes the protein in those foods as similar to those found in
pollen since they're biologically related.
This process is called cross-reactivity: an
allergic reaction to allergens similar to the ones you're allergic to.
Patients with hay fever are most likely to experience this. Birch,
alder, ragweed, mugwort, Timothy grass, and orchard grass pollen cause
most OAS symptoms, although birch and mugwort are the main culprits, as
they're related to many fruits that can trigger a reaction.
Interestingly enough, the syndrome will not typically appear in young
children, which is the time you should be exposed to all kinds of
allergens to lower the chances of allergy later in life. OAS symptoms
start showing mostly in adolescence as a reaction to fruits you may have
eaten before with no allergic reaction.
Keep in mind that OAS is not the same as the tingling or stinging you
get when you eat kiwi or pineapple. These fruit cause tinling because of
their high acidity and enzymatic content.
OAS and seasonal allergies
While symptoms may be at their peak during
spring, OAS can happen at any time of the year because different trees
pollinate during different seasons. For example, birch tree pollen is
the highest during spring, but mugwort pollen is mostly present in the
air during fall. This means that if you have an allergy to birch pollen
and you react to peaches during spring, you may be able to enjoy them
symptom-free through the colder seasons when there is no birch pollen!
In the summer, symptoms are more likely to
happen with peaches, tomatoes, and watermelon. In the spring, there are
many more fruits that may cause this cross-reactivity, as so many plants
are in bloom, enriching the air with pollen. Refer to this table by the
American Academy of Allergy Asthma & Immunology to see which fruits
may cause a reaction.
Here's another example to help you understand how to read the table: if
you're allergic to ragweed pollen, which blooms during late summer to
fall, you may experience a mild allergic reaction to cantaloupe during
bloom season, but not necessarily during the rest of the year. Plums,
pears, and peaches will be fine all year round. They may only bother
people with birch or grass allergies.
What can be done?
OAS is mostly not life-threatening. It's
generally considered a mild form of food allergy. Symptoms usually go
away on their own a few minutes after you've stopped eating the
allergen, or in severe cases, after you've taken an antihistamine.
However, if you experience allergic symptoms after ingesting any kind of
nut, you're advised to see a doctor to rule out any possibility of nut
allergies, which can become life-threatening.
There is no test to see if your reactions qualify as OAS. What you can
do is find the corresponding pollen that you are or may be allergic to
and take a test to verify.
Do note that it hasn't been proven
successful to resolve the syndrome or desensitize yourself by eating
more of the fruit. If symptoms are severe and interfere with daily life,
you can go through immunotherapy (regular allergy shots that
desensitize your body to the allergens).
Try cooking the fruits. The heat alters the protein in the fruit,
and it's not similar to the pollen anymore. You can also have canned
fruit. Try baking fruit pies or enjoying vegetables in a gratin (click
the links for recipes). You can even use the microwave to cook your
fruit or veggies.
Most of the protein is found in the peel and the core of the fruit.
Try peeling and coring an apple, for instance, to reduce its allergen
content.
If your symptoms are mild, explore different varieties. You may be
reactive to a granny smith apple, for example, but a pink lady apple
won't bother you in the slightest.
When should you see a doctor?
- Symptoms are getting progressively worse;
- Symptoms are caused by cooked fruits and vegetables;
- Symptoms are caused by nuts;
- You develop systemic reactions.