Has your child ever told you that certain foods cause tingling and itching in and around the mouth and the back of the throat? Does this occur within minutes of eating the food?
If your child also has seasonal allergies, it’s likely that this reaction is oral allergy syndrome. These symptoms occur because the proteins in some fruits and vegetables are similar to proteins in some pollens. These proteins can confuse the immune system and cause an allergic reaction or make existing symptoms worse.
People who are allergic to any type of pollen have a 50 percent chance of developing oral allergy syndrome. One of the most common types of cross-reactivity involves birch tree pollen and apple. Other food triggers associated with this pollen include peach, pear, kiwi, plum, coriander, fennel, parsley, celery, cherry and carrot. When one makes antibodies to the pollen, they also become sensitized to these fruits and vegetables. The Philadelphia area has an abundance of birch pollen and oral allergy syndrome is quite common here.
Most children and adults with oral allergy syndrome will experience symptoms only when eating fresh fruits and vegetables and, sometimes, nuts. In most cases, these foods are tolerated when cooked because cooking changes the shape of the food’s molecules so that the antibody doesn’t bind to the allergenic protein. So a person might be able to enjoy apple pie and applesauce without the symptoms that are caused by biting into a raw apple. However, a minority of patients cannot tolerate either the raw or cooked version of the food, and cooking may even increase the allergic potential of a protein, as in the case of peanuts.