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Oral Allergy Syndrome
Oral Allergy Syndrome

Oral Allergy Syndrome

Oral Allergy Syndrome is a food allergy in reaction to certain foods, nuts, vegetables and fruits. Most patients of “oral allergy syndrome” would have suffered from hay fever first. It is a pollen-food allergy caused by cross-reacting allergens found in pollens, raw fruits, vegetables, and some other nuts. As the name implies, it is a reaction that specifically affects the mouth, lips, tongue and throat. This pollen-food allergy syndrome is educed by a variety of plant proteins like PR proteins cross-reacting with airborne allergies. Ingestion of these cross-reactive plant foods causes oral allergy syndrome.

Typically, oral allergy syndrome doesn't occur in children, but likely happens in older children, teens and younger adults who have been eating fruits and vegetables for long without any complications at first. Younger children under three years old develop allergic rhinitis after they are toddlers. Most adult-onset food allergies are as a result of cross-reactions between foods and inhaled allergens which is triggered by IgE antibodies that bind to pollen proteins and structurally similar food allergens. It is often more prominent during the specific season for airborne pollen that corresponds to a seasonal rise in related IgE antibodies.


Some of the allergens associated with oral allergy syndrome:

  • Birch pollen: apple, almond, carrot, celery, cherry, hazelnut, kiwi, peach, pear, plum.
  • Grass pollen: celery, melons, oranges, peaches, tomato.
  • Ragweed Pollen: banana, cucumber, melons, sunflower seeds, zucchini.


Oral allergy syndrome is caused when your immune system identifies specific proteins in order to target bacteria, viruses, and other unwanted germs which leads to the syndrome. Theseproteins sometimes identified are harmful by the immune system, and affects our reactions to certain food or fruits after being eaten. It is mostly pollen-triggered.


Immediately after you eat fruits like cherries, apples or peaches, and develop itchiness around the area of your mouth, that's a possible sign that you might have oral allergy syndrome. You may also feel tightness in your throat, a sensation closing in on your throat, and seasonal allergies (rhinorrhea and sneezing) caused by an allergy to pollens.

Some other signs include: swelling of the mouth, lips and tongue or itchy ears. The symptoms sometimes are confined to a particular area and don't go beyond the areas of the mouth. A patient rarely develops the signs away from the mouth, or anaphylaxis from it. The swelling reduces once the raw fruit or vegetable is removed from the mouth or swallowed.

What treatment can be offered?

One of the ways to treat andmanage this allergy is the avoidance of the fruits and food in its raw forms that can cause oral allergy syndrome. To reduce the symptoms of OAS:

  • Cook and Heat your food. Heating your food changes the chemical composition and eliminates the allergen.
  • Buy canned vegetable or fruits instead.
  • Peel the back of the vegetables or fruit. The protein is often found in the skin of the produce.

With a combination of pharmacotherapy, this allergy can be held under control. Since Oral allergy syndrome leads to systemic reactions and anaphylaxis in some cases, the treatment of such reactions include indications for self-injectableepinephrine.