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Oral Allergy Syndrome

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Oral Allergy Syndrome or OAS is an allergic reaction to certain fruits, nuts, and vegetables. The reaction is more likely to occur with fresh forms of these foods. It is not an actual food allergy, but reactions to certain foods may develop in people with hay fever. The immune system mistakes the food proteins for the pollen proteins and causes an allergic reaction. See the chart on page 2 for a list of foods that may cause problems for people with pollen allergies.

The allergic reaction to these foods can occur anytime of the year when eating the foods but can be worse during the pollen season when your child is having hay fever symptoms. OAS is most common for people with spring allergy symptoms from birch pollen or late summer hay fever from ragweed pollen.

What are the symptoms of OAS?

An allergic reaction happens while eating the raw food. These reactions occur in the mouth and throat. This may also happen when peeling fruits or vegetables or it the juice touches the lips.

Symptoms of a reaction are:

  • itchy, tingly mouth, lips, throat
  • swelling of the lips, tongue and throat
  • watery itchy eyes
  • runny nose
  • sneezing

These more severe symptoms are rare:

  • vomiting
  • cramps
  • diarrhea
  • wheezing
  • cough
  • trouble breathing or swallowing

Severe allergic reactions to foods causing Oral Allergy Syndrome are most likely to occur with celery, kiwi, peaches, apricots, apples, and nuts, especially hazelnuts.

Tips for Management of Oral Allergy Syndrome:

  1. These reactions are usually caused by the raw fruit or vegetable. Your child may be able to eat the food if it is cooked, canned, micro-waved or baked. For example, someone allergic to raw apples can eat applesauce, apple jelly, apple juice, apple pie and dried apples. Try microwaving fruits and vegetables briefly.
  2. Nuts which cause Oral Allergy Syndrome should be totally avoided, whether fresh or cooked, because of the higher risk of severe reactions.
  3. For mild Oral Allergy Syndrome try peeling the fruit because the more allergic part of the fruit might be in the skin. The allergic reaction is not due to pesticides, chemicals or wax on the fruit. It is also better to give your child unripe or partially ripe fruits, or pick it directly from the tree so it is fresh. Freshly picked fruit and unripe fruit may cause fewer symptoms than fruit that has been stored for several weeks or very ripe fruit.
  4. If you child has had severe symptoms including trouble breathing, when eating any food, speak to your allergist as you may need to carry an epinephrine shot. Do not give your child that food in the future.
  5. Allergy shots for hay fever may sometimes help prevent symptoms associated with Oral Allergy Syndrome. 

Disclaimer: This information is not intended to substitute or replace the professional medical advice you receive from your child's physician. The content provided on this page is for informational purposes only, and was not designed to diagnose or treat a health problem or disease. Please consult your child's physician with any questions or concerns you may have regarding a medical condition.

Reviewed: 11/06

(757) 668-7000