OAS – When Raw Fruit is Forbidden
From the Allergic Living archives. First published in the magazine in 2009.
A life with OAS means only cooked or baked fruit. Crisp, raw fruit, how I miss you.
Cradling a fresh, succulent peach in my hands, I take in its tantalizing aroma. I rub the fuzz lightly on my lips before taking a big, juice-dripping bite. Delicious.
I swallow, and the tingling begins. First on my tongue, then throughout my mouth and my throat. Tingling becomes itching: there is no stranger feeling than an itchy tongue. That bane of the fruit-loving, Oral Allergy Syndrome, has kicked in.
OAS (also known as pollen-food syndrome) is an allergic reaction to certain proteins in a variety of fruits, vegetables and nuts. The symptoms include itching and burning of the lips, mouth and throat. In more serious reactions, there may be swelling of the mouth, back of the throat and windpipe as well as hives.
Those of us with the condition usually develop symptoms within minutes of eating the food, and they typically dissipate in less than 15 minutes. Just enough time to make a person go a bit crazy.
For me, the itching can be counteracted by eating a neutral substance such as bread or by drinking water. Fortunately, OAS is rarely severe.
“For the majority of people, this is not a real life-threatening problem like true food allergies,” explains Dr. Bruce Mazer, director of the division of allergy and immunology at Montreal Children’s Hospital and an associate professor at McGill University.
Raw vs. Cooked
OAS sufferers react to raw fruit, but are usually able to eat the same food cooked without a problem. “Typically we see OAS in people allergic to heat labile protein, which means those proteins easily destroyed by heat,” explains Dr. Paul Keith, an associate professor of allergy and clinical immunology at McMaster University in Hamilton.
“When you eat the fruit raw, it’s your own body’s heat that breaks down the protein, which is why the reaction doesn’t move beyond the mouth, says Keith, who’s also an investigator for AllerGen, the allergy research network.
I know the raw versus cooked issue first-hand. When I eat uncooked fruits like apples, cherries, pears and my beloved peaches, they all cause itching. But bake them in a pie and I can eat to my heart’s content, without so much as a tingle.
I remember eating apples as a youngster with no problems, but then one day, my tongue got really itchy afterward. As my mother couldn’t see anything on my tongue, she assumed I was trying to get out of eating the fruit. Then it happened again, and with different fruits. Because they couldn’t see a problem, my parents thought I was just fussing. But they did stop giving me the troublesome fruits.
By my late teens, I started trying these fruits again, in small amounts. Sometimes I got an intense itch in my mouth and throat, sometimes it was minor. If I craved the juicy goodness, I’d eat the fruits anyhow – since the itch always went away.
Once, however, I ravenously ate a whole peach. This time itchiness turned to swelling: my lips got puffy and I felt like I couldn’t swallow. The episode subsided in half an hour. I was miserable, yet vindicated, since my parents finally believed there was an allergic reaction. We asked a couple of doctors, but no one could pinpoint the condition. They advised that I avoid the offending fruits like any major food allergy, and that put an end to my fruit infatuation.
Fortunately, awareness of OAS is growing. But how can you be sure if you have it?
Next Page: Diagnosing OAS