Oral Allergy Syndrome and Hay Fever: Facts and Management Tips
What Is Oral Allergy Syndrome?
Oral allergy syndrome (OAS) is a disorder in which the ingestion of a particular food causes an allergic response in the mouth. The most common symptoms of the disorder are a burning, itching, or tingling sensation in the lips, tongue, lining of the mouth, and throat. Oral allergy syndrome is generally less serious than a so-called "true" food allergy, which can cause a major and widespread allergic response. This isn't always the case, however.
Most people who experience OAS also suffer from hay fever. In fact, an allergy to pollen is believed to be responsible for most cases of oral allergy syndrome. Hay fever is caused by proteins in inhaled pollen grains that trigger an attack by the body's immune system. Some foods contain similar proteins to those in pollen grains and also trigger an immune system attack. The system is unable to tell the difference between the proteins in the pollen grains and the proteins in the food, a phenomenon known as cross-reactivity.
OAS can occur all year found, but for some people it's worse in the pollen season. Strategies to reduce or prevent both hay fever and OAS may be useful. I have both of the disorders and find some of the techniques described below very helpful for relieving them.
Oral allergy syndrome is sometimes known as pollen-food syndrome or pollen-food allergy syndrome. It's an annoying but generally mild condition. In cases where symptoms that might indicate its presence are more severe, it's important to consult a doctor.
In many people, symptoms of oral allergy syndrome are localized and are restricted to the mouth. The first symptom listed below is most common and may be the only one that appears. OAS symptoms usually develop immediately after eating a food, but they may not develop until up to thirty minutes later or very occasionally up to an hour after eating the allergenic food.
- A burning, itching, or tingling sensation in the lips, mouth, and throat
- Swelling of the lips, tongue or throat
- Runny nose
- Itchy eyes
Occasionally, symptoms may appear beyond the mouth and face. This situation requires a medical consultation.
- Nausea, vomiting, or diarrhea
Oral allergy syndrome is uncomfortable but is generally not dangerous. Very occasionally, OAS can be a serious condition. The tissues in the mouth and throat may swell so much that they block the airways, which is a medical emergency. A asthma attack may sometimes be an emergency, too.
Very rarely, OAS may lead to anaphylaxis, which is always a medical emergency. Anaphylaxis is a very serious, rapidly developing, and systemic (whole body) allergic response. Fortunately, the more serious symptoms of oral allergy syndrome are rare. It's estimated that only 1.7% of people with the condition experience anaphylaxis due to the disorder.
Pollen is produced by the male part of a flower, which is called the stamen. The stamen consists of a stalk called a filament bearing a sac called an anther. The anther contains the pollen grains.
Is the Problem Really Oral Allergy Syndrome?
Someone who suspects that they have oral allergy syndrome should mention this fact to their doctor. The doctor should be visited as soon as possible if symptoms are severe. Some food allergies can produce similar symptoms to OAS. For example, a soybean allergy can result in tingling and swelling in the mouth, nausea, and a runny nose when the bean is eaten.
It's important to discover whether an allergic response is a case of oral allergy syndrome, which usually affects a limited area in the body and causes relatively minor problems, or is actually a food allergy, which may have far-reaching and dangerous effects.
Doctors can order allergy tests to determine which type of pollen or food someone is allergic to. They can also suggest and prescribe treatments for hay fever, oral allergy syndrome, and food allergies.
Oral allergy syndrome is an unusual type of food allergy because the body is really responding to pollen proteins rather than food molecules. People generally develop OAS after being exposed to pollen grains and suffering from hay fever for years, as I did. Not all people with hay fever develop oral allergy syndrome, but many do. Some people with OAS don't experience hay fever.
The condition develops in older children, teenagers, and adults, but usually not in young children. It's a frustrating disorder because the sufferer finds that a food that they used to eat with no problem now causes unpleasant symptoms. It's especially annoying when this food is a favourite one or when several foods cause problems.
The table below shows the most common foods that can trigger OAS in people when they are allergic to a particular type of pollen. Other foods not mentioned in the table may have the same effect. If a person responds to one food in a category, they don't necessarily respond to other foods in that category.
Unless it's obvious that a particular food produces oral allergy syndrome or another allergic response, a nutritious food shouldn't be dropped from the diet. There are a lot of very nutritious foods listed in the table of suspect foods below, especially in the case of a birch pollen allergy. It would be a great shame to eliminate any of them unnecessarily.
Cross-Reactivity Between Pollen and Food
Pollen That Triggers Hay Fever
Possibly Allergenic Fruits
Possibly Allergenic Vegetables
Possibly Allergenic Nuts or Seeds
bananas, cantaloupes, honeydew melons, watermelons
cucumber, zucchini, chamomile, Echinacea
oranges, kiwi fruits, melons
tomatoes (which are technically a fruit)
apples, pears, kiwi fruits, peaches, apricots, nectarines, plums, prunes (dried plums), cherries
carrots, parsnips, celery, potatoes, fennel, parsley, beans, peas, lentils, peanuts, tomatoes, green peppers, coriander, anise
hazelnuts, almonds, walnuts
apples, pears, peaches, cherries
carrots, parsnips, celery, green peppers, parsley
Possible Ways to Prevent Symptoms
The only way to be certain of avoiding oral allergy syndrome is to completely avoid any allergens in the diet. This is not as easy as it sounds, however. Sometimes allergenic foods are mixed with non-allergenic ones in items like salads, soups, stews, spice mixtures. and supplements. It may not be advisable to buy these items in stores or restaurants unless the ingredients are known.
Avoidance of some problematic foods may not be necessary. There are certain food preparation techniques which may enable a person to eat a food that otherwise produces OAS. One advantage of oral allergy syndrome proteins compared to the allergenic proteins in a true food allergy is that the OAS ones tend to change their shape or break down when heated. This may prevent the immune system from recognizing them.
Food Preparation Techniques
Many people with oral allergy syndrome can eat allergenic foods if they prepare them in a certain way. Please note that if you have experienced a serious case of oral allergy syndrome or if you have a true food allergy, none of the food preparation techniques described below must be tried. The food that you are allergic to must be completely avoided. For people who experience mild to moderate oral allergy syndrome, though, the following strategies may enable some problematic foods to be eaten.
Eat Cooked Food
Cooking breaks down some of the allergenic proteins in food, so an allergy sufferer may tolerate the cooked food but not the raw food. This is the case for my reaction to hazelnuts. When I eat the raw nuts I experience oral allergy syndrome symptoms. Generally, when I eat hazelnut butter made from roasted hazelnuts I don't experience any symptoms. I say "generally" because I have occasionally eaten hazelnut butter that has made my throat sore.
Some allergists recommend that if a person has a reaction to raw nuts they should eliminate them from the diet instead of cooking them or preparing them in a different way, since nuts are so allergenic.
Cooking food is often very helpful for oral allergy syndrome. Many OAS sufferers can eat apple pie, apple sauce, and pasteurized apple juice, but not fresh apples, for example.
Eat Canned Food
During the canning process, food is heated. This may be helpful for OAS sufferers. Fresh peaches or pears may trigger OAS symptoms, for example, while canned ones may not.
Eat Peeled Food
Sometimes the allergenic proteins causing OAS are located in the peel or skin of a fruit, vegetable, or nut. Peeling the food may prevent symptoms. Peeled or cooked apples are fine for me, but if they are raw and are still covered with their skin they trigger OAS symptoms.
The American Collegy of Allergy Asthma & Immunology says that a doctor should be visited if cooked fruits, cooked vegetables, or nuts trigger OAS or if symptoms include vomiting, difficulty in breathing, or hives.
Possible Medical Treatments
If none of the above techniques work for you or if your allergic response is becoming worse, visit your doctor. The doctor may prescribe an antihistamine. Histamine is a chemical produced by the immune system to help it fight invaders. Unfortunately, it also produces the unpleasant symptoms of allergies. Antihistamines prevent histamine from binding to cells and doing its job.
If a person has a serious case of OAS which causes potentially dangerous swelling in the air passages, the doctor may prescribe an epinephrine auto-injector. Epinephrine is a chemical that expands the airways when they constrict. It's rarely needed in oral allergy syndrome, however.
Another possible treatment is immunotherapy, or allergy shots. The therapy starts with the patient being given a tiny dose of the allergen. As time passes, the dose gradually increases until a maintenance dose is reached. This treatment can cause the body to develop a tolerance to the allergen.
Immunotherapy is generally prescribed only for people with severe hay fever symptoms. It has helped hay fever sufferers. The results of immunotherapy for OAS treatment have been variable, however. Some OAS sufferers have been helped by the treatment while others have not.
Common Hay Fever Symptoms
Hay fever results from the overactive response of the immune system to pollen grains. It often develops in spring, since allergenic plants such as birch and alder produce their catkins then. These catkins release pollen. In this case hay fever is often referred to as a spring allergy or as "spring allergies". Some plants, such as ragweed, release their pollen later in the year, so hay fever isn't restricted to spring.
Hay fever is also known as seasonal allergic rhinitis. Rhinitis is a condition in which the airways are inflamed due to an allergic response. The condition can be very unpleasant, but it isn't a type of fever, despite its common name. The most common symptoms are listed below.
- Frequent sneezing
- Nasal congestion
- Runny nose
- Itchy, watery, and red eyes
- Itchy nose, throat, and/or ears
The sneezes can be so frequent that they interfere with life and stop a person from doing from what they need to do.
The Pollen Season
In people who suffer from both hay fever and oral allergy syndrome, when the immune system goes into overdrive to attack pollen proteins it's also being primed to attack similar proteins in food. Reducing the overactivity of the immune system during the pollen season may help to reduce the strength of oral allergy syndrome. Some people have reported that this strategy is helpful, but not everyone has found it to be beneficial. I can't say with certainty that's it's helped me because I use food preparation techniques to prevent OAS. The effort to reduce hay fever is worthwhile, though, because it reduces the misery of the allergy season.
According to the National Health Service in the UK, 75% of people with an allergy to silver birch pollen also experience oral allergy syndrome.
How to Reduce Hay Fever Symptoms
The following strategies will decrease a person's exposure to pollen and should help to reduce hay fever symptoms.
- Stay indoors with the windows and doors shut during times of high pollen counts. An air conditioned building is useful in summer.
- Check the pollen forecast daily. Some weather forecast websites let visitors enter the name of a city to see the local pollen forecast. The sites also tell the visitor whether the pollen count is considered to be high, moderate, or low.
- Set air conditioners to recirculate air so that they don't bring in fresh pollen.
- Try to limit outdoor exposure during the time of day when the pollen that you are allergic to is released.
- Pollen counts are high during warm, dry, and windy weather but fall during rainy weather. Exercising during rain or right after rain has stopped is best for a hay fever sufferer who wants to exercise outdoors.
- Consider wearing a mask to filter out pollen grains and wrap-around sunglasses to protect your eyes if your hay fever is bad. A scarf over the nose and mouth will also help to prevent the inhalation of the grains.
- Keep car windows closed.
- Attach a filter that traps pollen grains to the air vents of your car.
- Avoid mowing the lawn or gardening during the pollen season. Don't bring flowers into the home.
- Try placing vaseline in the lower part of your nostrils to trap pollen grains.
- Wash nostrils and eyes with saline solution to remove the grains.
- Wash your skin, hair, and clothing after exposure to the particles.
- In your home, use an air filter that traps pollen grains.
- Use a vacuum with a filter that traps the grains.
- Wet-dust to avoid sending pollen particles into the air.
- Don't dry clothes outdoors.
Other Strategies That May Be Helpful
Some allergy experts suggest avoiding exposure to pets whose coat has collected pollen grains. Some even suggest keeping the pets outside. That's never going to happen in my home. I wouldn't dream of leaving my pets outside or of paying them less attention. If you feel the same way, it might be helpful to ask someone else in the family to brush the pet before he or she comes inside if they have been outside for a long time.
Antihistamines can be bought in drug stores and can be very effective for preventing hay fever symptoms. Doctors can prescribe more powerful ones if necessary. It's important that non-drowsy antihistamines are used. Sedating ones can be dangerous for drivers and can interfere with school or work. Even when antihistamines are used, though, pollen avoidance techniques may be a good idea in someone with hay fever and OAS.
Depending on food choice, it may be possible to eliminate oral allergy syndrome symptoms. Eliminating all hay fever symptoms depends on how sensitive a person is to pollen. There are always some pollen grains in the air. Pollen avoidance techniques and medical treatments can be a big help, though. They can greatly reduce symptoms and in some people eliminate them altogether.
- Information about Oral Allergy Syndrome or OAS from the American Academy of Allergy Asthma & Immunology
- "Foods That May Trigger Pollen Allergies" from WebMD
- Facts about oral allergy syndrome from the National Health Service
- "Oral Allergy Syndrome" from the Canadian Food Inspection Agency
- A report about oral allergy syndrome from the Canadian Medical Association Journal
- Hay fever information from the Mayo Clinic
- Facts about hay fever from the National Health Service.
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2014 Linda Crampton