Oral allergy syndrome - related to pollen allergies
by: Jessica Woodward, M.D.
We’ve all heard of seasonal allergies. The condition is characterized by an immune response to pollen from trees, grasses or weeds. In other words, the immune system treats pollen as a foreign invader, prompting symptoms of sneezing, coughing, nasal congestion, itchy watery eyes, nose and throat. Symptoms usually occur during certain times of the year, when pollen is in the air. According to the Center for Disease Control, 7.5 percent of adults and 9 percent of children in the U.S. experience seasonal allergies, also known as allergic rhinitis.
Some people with seasonal allergies also have a reaction when they eat certain raw fruits, vegetables and tree nuts. This response occurs because the proteins found in these foods are very similar to those found in pollen. The body confuses the food with pollen and an allergic reaction occurs. This condition is called oral allergy syndrome (OAS) and is not a separate allergy but rather a cross-reactivity that occurs when body perceives proteins in the trigger foods as pollen.
In OAS, symptoms include itchy mouth and tongue, scratchy throat, and swelling in the mouth and lips. Less common symptoms include itchy watery eyes, itchy ears, runny nose and sneezing. The symptoms usually come on quickly – within minutes of eating the trigger food – and are typically confined to the mouth. They also usually subside quickly and do not require treatment. After the food is swallowed and moves through the digestive tract, stomach acids destroy the allergens.
If you or someone you know experiences a reaction beyond the mouth area, the food could be considered a risk for anaphylaxis, a serious reaction that has a rapid onset and could lead to swelling of the throat and could cause death. While anaphylaxis is rare, it is serious and requires immediate medical attention and ongoing treatment.
Not everyone who has seasonal allergies experiences OAS. According to the American Academy of Allergy, Asthma & Immunology, up to a third of pollen allergy patients may experience OAS, with onset occurring during the teen or young adult years. With OAS, a person may only have an allergic reaction to one food, while another may have a reaction to a number of foods. Sometimes OAS starts with a reaction to one food and more develop over time. OAS can occur at any time during the year but is more prevalent during the pollen season.
Three common types of OAS are associated with seasonal allergies to birch pollen, grass pollen and ragweed pollen. Each has its own common food triggers.
People with an allergy to birch pollen may have an oral reaction to apples, apricots, cherries, kiwi, peaches, pears, plums, carrots, celery, parsley, peanuts, soybeans, aniseed, caraway, coriander, fennel, almonds and hazelnuts.
Those with a grass pollen allergy tend to react to melons, oranges, peaches, celery, tomatoes, Swiss chard, white potatoes and peanuts.
Finally, ragweed pollen allergy sufferers often react to bananas, melons, cucumber, zucchini, sunflower seeds and chamomile tea.
There is no specific treatment for OAS, but because it is an offshoot of pollen allergies, it is most often treated like a pollen allergy, not a food allergy. Using medications and treatments available for seasonal allergy sufferers to treat OAS may decrease or eliminate symptoms for some people.
Another way to avoid symptoms? Avoid trigger foods. Usually only raw fruits or vegetables cause OAS symptoms; cooking the foods breaks down the trigger proteins so the immune system doesn’t target them. Canning foods breaks down the proteins in a similar way as does freezing and pasteurization. Also, most of the trigger proteins are located in the peels of the foods, so removing the peel may help to prevent symptoms.
If eating raw apples, peaches or almonds puts your mouth into a state of itchiness, and you suffer from season allergies, there’s a chance you are experiencing oral allergy syndrome, a product of your allergy to pollen. While annoying, OAS isn’t usually serious and can be avoided by cooking trigger foods or staying away from them all together. If you suspect you might be experiencing OAS, you should discuss your symptoms with your doctor.
Dr. Woodward is a board certified family practice physician at Raiter Clinic in Cloquet.