In most people, OAS is a relatively mild allergic response, and people who have it can eat the vegetables or fruits that cause inflammation and itchiness in their throat and mouths – as long as those foods are cooked.

The reason for this? OAS sufferers are only allergic to the “heat labile proteins” – the proteins in the fruit that get destroyed once exposed to heat.

This explains why the symptoms are confined to the mouth: “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 Dr. Paul Keith, an associate professor of allergy and clinical immunology at McMaster University in Hamilton, Ontario.

So while a raw apple a day might keep the person with OAS away, she can eat a slice of apple pie without a problem. The same goes for vegetables. While celery or carrots and dip may make your lips puff up, a nice hearty vegetable soup will go down smoothly.

There are some tricks you can use to try to cheat nature – but they may not work for everyone. Dr. Bruce Mazer, director of the division of allergy and immunology at the Montreal Children’s Hospital and associate professor at McGill University in Montreal, suggests microwaving the fruit, like an apple, for a few seconds.

He also suggests sprinkling lemon juice on the raw fruit and letting it sit for a few minutes before eating. These tricks may help to break down those heat labile proteins while still allowing the fruit to be somewhat crisp. You can also simply try peeling the fruit first since most of the fruit’s proteins are in its peel. Of course, this would only help for fruits that have a peel and not for fruits like raspberries and strawberries.

Dr. Keith approaches management from a different angle. He suggests trying to better control the hay fever so that your body will no longer recognize the offending proteins, even in the related fruits and vegetables. This can be done by using saline nasal sprays to keep the nose clear, wearing glasses to protect the eyes, and keeping windows and doors closed to lessen exposure to pollens.

Spring is here: temperatures are rising, trees are blooming and spring fever hangs in the air. But for many people, the season brings on a fever of a different sort – the mad rush to manage tree pollen allergies.

Across America, virile male trees are busily spreading their highly allergenic pollen. The microscopic grains float around like a fog, blanketing some areas with a yellowish-green mist. Even when you can’t see pollen, it’s there, causing up to 40 million Americans to endure itchy eyes, painful congestion, running noses and sleepless nights.

Certain trees are notorious pollinators. Gender also plays a role: male dioecious (separate sexed) trees trigger the worst reactions, although monoecious (dual sexed) aren’t much better. Since avoidance is one of the strategies to fight hay fever, it’s helpful to know which trees are the most allergenic – and where to find them. So grab the road map and an antihistamine; it’s time for Allergic Living’s tour of the worst pollen offenders.

Tree Pollen Allergy Tour: Western States

Juniper trees make spring the sneezing season in Colorado, says Susan Kirkpatrick, a certified pollen counter and an asthma educator with The William Storms Allergy Clinic in Colorado Springs. Poplar, cottonwood, aspen, elm, maple, alder and oak trees bring a parade of unhappy patients into clinics, too.

Finally, Coloradans should also beware the lodgepole pine, says Thomas Ogren, a horticulturist and author of Allergy-Free Gardening: The Revolutionary Guide to Healthy Landscaping.

In Washington state, it’s the cedar, juniper, alder, birch, poplar and cottonwood trees that bring on hay fever symptoms, says Dr. Frank Virant, who heads the division of allergy at Seattle Children’s Hospital. Also sure to trigger allergies for some western residents are walnut and holly trees.

Down in California, the eucalyptus tree is emerging as a cause of seasonal symptoms –  perhaps no surprise, given its ubiquity. “They say that you can drive from San Francisco to San Diego along the coast and never be out of sight of a eucalyptus tree,” says Ogren.

The silver wattle, almond and casuarinas (also known as beefwood or she-oaks) are some other relatively common allergy-producing trees in the west. Not to mention camphor trees. “The streets of Los Angeles are lined with camphor trees that are 100 years old and they’re gorgeous,” says Ogren. “But the people who live on those streets get quite miserable.”

The allergy prone ought to also be wary of these other California trees: Catalpas (also called stogie trees, as native Indians used to dry the leaves, cut off the ends and smoke them like cigars); bottle brush, whose red flowers resemble baby-bottle brushes; Cryptomeria (also called Japanese cedar, these trees are the No. 1 cause of allergy in Japan, according to Ogren); Cyprus trees; box elder and ash-leaf maple.

Next page: Allergy trees in South Central U.S.