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By Dr. Anthony Ham Pong, M.B., B.S., Paediatric Allergist - Ottawa Ontario.
Published in the June 2000 AAIA newsletter.

Oral Allergy Syndrome is an allergy to certain raw fruits, vegetables, seeds, spices and nuts causing allergic reactions in the mouth and throat. These allergic reactions happen mostly in people with hayfever, especially spring hayfever due to birch pollen, and late summer hayfever due to ragweed pollen (Webmaster note: there is no ragweed pollen in British Columbia west of the Rockies).

An allergic reaction happens while eating the raw food, and causes itchy, tingly mouth, lips, throat and palate. There may be swelling of the lips, tongue and throat, and watery itchy eyes, runny nose and sneezing. Handling the raw fruit or vegetable e.g., peeling it or touching the juice to the lips, may cause rash, itching or swelling where the juice touches the skin, or sneezing, runny nose and water eyes. Sometimes, more severe symptoms can happen such as vomiting, cramps, diarrhea and, on rare occasions, life threatening reactions with swelling of the throat, wheezing, trouble breathing and anaphylaxis.

Ragweed allergy (which causes hayfever in August and September) can be associated with allergies to raw bananas, and the members of the gourd family (melon, watermelon, honeydew, cantaloupe, zucchini and cucumber).

Grass allergy can be associated with allergies to orange, melon, watermelon, tomato, kiwi, peanut.

These allergic reactions usually occur only when the food is raw. People who are allergic to the raw food can eat it cooked, canned, microwaved, processed or baked. For example, someone allergic to raw apples can eat apple sauce, apple jelly, apple juice, apple pie and dried apples. However, nuts may cause allergic reactions whether raw or cooked. This problem is usually life long. Allergy tests to these foods may sometimes be negative unless a fresh fruit is used for the test (instead of a commercial allergy extract). The allergic reaction to these foods can occur anytime of the year when eating the foods but can be worse during the pollen season and especially if hayfever is very troublesome that year.

The allergic reaction is not due to pesticides, chemicals or wax on the fruit. Howeve,r because the more allergic part of the fruit may be in the skin, some people allergic to fruits, e.g., peaches, can eat the flesh without reaction if the skin is peeled away. Similarly for apples, some brands of apples cause more allergic reactions than others. Freshly picked apple, e.g., straight from the tree or an unripe apple, may cause fewer allergic reactions than one which is very ripe or one which has been stored for weeks after picking.

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

Management of Oral Allergy Syndrome

1. These allergies are caused by the raw fruit or vegetable and therefore, once they are cooked or processed, they can usually be eaten.
2. You do not need to avoid all the foods on the chart in the table above. Avoid only those particular ones which have caused allergic reactions.
3. Be aware, however, that if you do have Oral Allergy Syndrome to some of the foods, you can develop allergies to other foods on the chart.
4. If an allergic reaction occurs to one of these foods, stop eating it immediately. Severe reactions may happen if you keep eating that food. Allergic reactions may be treated with antihistamines.
5. If you have had severe symptoms including trouble breathing, when eating the foods, you may need to carry injectable medication with you to treat these reactions (e.g., EpiPen®).
6. For mild Oral Allergy Syndrome, try peeling the fruit, or eating unripe or partially ripe fruits, or picking them directly from the tree so that they are quite fresh. If you react, do not keep eating the food.
7. Microwaving briefly to a temperature of 80°-90° C (176° - 194° deg F) may allow you to eat the food.
8. Nuts which cause Oral Allergy Syndrome should be totally avoided, whether fresh or cooked, because of the higher risk of severe reactions.
9. Allergy shots for hayfever may sometimes help associated food allergies.
   
   

Substitute Raw Fruits
Berries* (strawberry, blueberry, raspberries, etc.), citrus* (orange, mandarins, etc.), grapes, currants, gooseberries, guava, mango, figs, pineapple, papaya, avocado, persimmon, pomegranates, watermelon*.

Substitute Raw Vegetables
MUSTARD family (cabbage, cauliflower, broccoli, watercress, radish
GOOSEFOOT family (spinach, swiss chard)
COMPOSITE family (green onions)

Substitute Nuts
Peanut*, cashew, pistachio, brazil, macadamia, pine nut.

*May occasionally cause Oral Allergy Syndrome.

Allergy/Asthma Information Association,
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This article courtesy of the Allergy/Asthma Information Association at www.aaia.ca and the Calgary Allergy Network web site at www.calgaryallergy.ca. May be reproduced for educational, non-profit purposes with proper attribution.
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