All About Oral Allergy Syndrome

Mother always told you to eat your fruits and vegetables. Sometimes, Mother was wrong.

A less severe form of food allergy, called oral allergy syndrome, is a reaction to proteins in common raw fruits, vegetables, nuts and seeds. It’s called “oral allergy” syndrome or OAS because its symptoms are usually limited to the lips, mouth, tongue and throat.

Estimated to affect about one-third of pollen allergy sufferers*, oral allergy sydrome (sometimes called pollen allergy syndrome) is more widespread than the higher profile – and more dangerous – allergies to peanuts, dairy and eggs.

If you have oral allergy syndrome, chances are that you also have allergies to pollen from trees such as birch and alder, and/or to pollens from ragweed and grass.

Think of it as an allergy by association – or a cross-reaction – because your immune system, already primed to attack tree, plant and grass pollens, does not recognize the subtle differences between their proteins and those contained in foods as basic as an apple.

Not Usually Life-Threatening

One reason for oral allergy syndrome’s lower profile is that, unlike other food allergies, its symptoms are not usually life-threatening. Another is that it is relatively easy to avoid.

“You may eat something that contains traces of peanut, dairy or egg, but you aren’t going to unknowingly bite into a raw apple,” notes Dr. Antony Ham Pong, an allergist and based in Ottawa.

High Incidence of Oral Allergy Syndrome

About 10 per cent of the population**, or roughly one-third of North Americans with pollen-related allergies, are thought to be affected by OAS.

Ham Pong says he usually first sees patients when they’re between 8 to 10 years old. It’s not clear, however, why no more than one-third of hay fever sufferers are affected.

Next: More Serious Oral Allergy Symptoms