Oral Allergy Syndrome: The Potentially Deadly Allergic Reaction You May Not Know About

One hot summer day when I was eight years old, my mother, younger brother, and I had been working hard outdoors in the garden. My mother decided to reward us with slices of cold, chilled cantaloupe.

To our horror, about half an hour after we had eaten our natural treat my mother’s face began to swell. Her eyes swelled shut, her cheeks puffed outward, and she was having so much trouble breathing she could not speak.

In those days, there was no 911 to call, but fortunately my father came home early from work. He placed her in our family’s 1951 Mercury and raced her to the local doctor for a life-giving shot of epinephrine. She only recovered after several days in the hospital. My mother had experienced severe oral allergy syndrome.

Oral allergy syndrome refers to food allergy symptoms involving the mouth and throat. The name doctors give this condition reflects the importance of direct contact of the lining of the mouth and throat with offending foods to trigger local symptoms such as itch, swollen lips, and “closing up” of the throat. Oral allergy symptoms arise almost immediately (within 1 to 5 minutes) after eating the offending food. Certain combinations of foods may cause symptoms that individually do not.

Symptom summary:

Severe and sudden allergic symptoms of varying intensity

Itching in the mouth

Swollen lips

Swollen eyes

Sneezing

Blistering of the skin of the face

Nausea and vomiting

Hive-like swelling of the throat

How common is oral allergy syndrome? It varies by the food causing symptoms. In one study of 1,537 people who had food allergies, almost 95 percent of people who were allergic to tomatoes developed oral allergy syndrome shortly after eating them. The percentage drops to 72 percent for people who are allergic to walnuts, that is, allergies to walnuts are less likely to come on quickly and less likely to involve the mouth and throat.

Corresponding levels of vulnerability to oral allergy syndrome are 63 percent for people allergic to apples, pears, peaches, and plums, 44 percent for people allergic to vegetables other than tomatoes, 30 percent for people allergic to peanuts, 29 percent for people allergic to soy, 25 percent for people allergic to wine, 13 percent for people allergic to fish, and 8 percent for people allergic to spices. People who have oral allergy syndrome are the people in danger of life-threatening allergic reactions.

Oral allergy syndrome is much more common in adults than in children. It is very rare in children under 10. It is more common in adults who have an allergy to tree pollens, and is very common in people who are allergic to latex. Typically, symptoms occur very soon after the culprit food comes into contact with the oral mucosa, but some foods cause faster reactions than others.

Nuts and peanuts, for instance, may cause symptoms in just a few symptoms. Cantaloupe and other melons may not cause any symptoms for 30 minutes. Life-threatening reactions to peanuts are well known, but the most common cause of glottal edema, hives in the throat that cut off breathing, is celery.

Here's what to do. Avoid any fruit or vegetable that has ever caused you symptoms of oral allergy syndrome and avoid the following combinations:

1. Peanuts and almonds, Brazil nuts, hazelnuts, or walnuts
2. Any kind of nut with apricots, peaches, or plums.
3. Apples and pears together.
4. Avocado and kiwi at the same meal.
5. Carrots and Irish potatoes at the same meal.
6. Celery and parsley at the same meal.
7. Corn and peaches at the same meal.
8. Two or more foods from the following list at the same meal: apple, carrots, celery, green beans, hazelnuts, parsley, and Irish potatoes.

One of the peculiarities of oral allergy syndrome is, if you are allergic to one fruit or vegetable, you are especially likely to be allergic to another. The sequences of amino acids that trigger oral allergy syndrome are found in different kinds of foods. For instance, the same allergenic amino acids are found in apple, carrots, celery, green beans, hazelnuts, parsley, and Irish potatoes.

Eating just one of these foods at a meal may cause you no problem at all. Eating all of them at the same meal maximizes your risk of suffering oral allergy syndrome. If you are allergic to corn, you are likely to be allergic to peaches. If you are allergic to latex, you are likely to be allergic to avocado, banana, chestnuts, kiwi, papayas, and potatoes, and you should avoid eating two or more of these foods at the same time.