Many people with allergic rhinitis A.K.A. hay fever symptoms develop oral allergies to particular foods.
Up to 70 per cent of those with an allergy to birch pollen, for example, will be affected by oral allergy symptoms. They will react to some vegetables and fruits such as apples and/or plums, and possibly some nuts.
Alder tree pollen might cross-react with foods like apples, almonds, celery, cherries, hazelnuts, peaches, pears, and parsley.
The cross-reactivity between pollen and particular foods is known as an oral allergy syndrome (OAS) A.K.A. pollen-food syndrome. Oral allergy syndrome is an allergic reaction affecting mainly the mouth and throat, to certain proteins in fruits, vegetables and nuts. The protein in these foods share a similar shape and structure to the protein related to pollen, setting off a short-term reaction.
Not everyone with some kind of a pollen allergy develops this hypersensitivity to certain foods. Roughly 25 percent of those with significantly bothersome hay fever symptoms that are sufficient enough to require medication to make it through the allergy season, may experience oral allergy syndrome.
Below are our 10 facts about oral allergy syndrome and its link to hay fever symptoms.
- The Digestive Link: Oral allergy syndrome happens when the plant proteins responsible for triggering the allergic reaction, fail to survive their way through the digestive system and instead get destroyed by digestive enzymes and stomach acids.
- Do Not Confuse with Classic Food Allergy: In a food-pollen allergy, pollen is the primary problem. In a classic food allergy (for example, to shellfish or peanuts) – it is a foreign protein found in the food itself. If this foreign protein, called an antigen, travels through the digestive system and ends up getting absorbed, the immune system reacts via a body-wide, not localized effect. That’s why with a true food allergy you may see allergy symptoms such as hives, cramping, diarrhea and pain.
- Symptoms Develop Fast! When related to hay fever symptoms, oral allergy syndrome reactions usually develop within a few minutes to over an hour after eating or touching or peeling the offending food. Hay fever symptoms almost always preceed oral allergy syndrome reactions. Also, the reactions tend to occur most often in adults and older children.
Common symptoms include:
- itching and burning of the lips, mouth and throat
- Itchy watery eyes
- runny nose
- Possibly a rash, itching or swelling of the area where the food came in contact with the skin
More serious and less common reactions include:
- swelling of the mouth, pharynx and windpipe
In rare cases, reported severe allergic reactions include:
- vomiting and diarrhea
- bronchial asthma
- generalized hives
- anaphylactic shock
4. Most Reactions Are Caused by Raw Food: When it comes to food-pollen allergy, most adverse reactions of the immune system are caused by raw foods. The allergenic proteins associated with oral allergy syndrome as connected to the hay fever symptoms are usually destroyed by cooking.
5. Cooking and Processing of Food Alter Allergy-Causing Proteins: The good news is that the exact same vegetables and fruits that trigger food-pollen allergy syndrome symptoms when eaten raw, can be consumed without any of these side-effects when cooked instead! Only the fresh food and not baked, canned, cooked or microwaved causes the reaction. All this suggests that heating or cooking food destroys the allergenic proteins in it. So eating a slice of apple pie or a spoon of applesauce would not cause a reaction in individuals who would normally react to a bite of a fresh apple (organic or conventionally grown – no difference). Dried apples or apple jelly should not cause a problem, either. When eating a fresh apple, for instance, your mouth may react as though it had been exposed to birch pollen. So your mouth and throat might get itchy.
6. Beware Exceptions! The main exceptions to the “safe cooked foods list” are celery and nuts. These may actually cause food- hay fever reactions even after being cooked as they are resistant to processing.
7. Part of the Food Item Matters: Some vegetable and fruit parts, such as the skin, may be more allergenic than other parts. Therefore, it is a good idea to peel raw foods.
8. Longer Shelf Life May Help: The allergic characteristics of certain fruits seem to decrease during storage. Moreover, ripe fruits are often easier to digest than unready ones that may cause gas even in the healthiest people!
9. Beware Foods Associated With Anaphylactic Reactions! Certain foods associated with oral allergy syndrome and hay fever symptoms, may cause potentially life-threatening anaphylactic reactions.
Although these are rare, observe your body’s response to the following foods and note that some entries may be surprising to most people:
- white potato
10. Not Every Allergy-Prone Food is Linked to Hay Fever Symptoms: Some fruits and their juices may sometimes cause a skin rash and diarrhea, especially in younger children, on their own, without being associated with an oral allergy syndrome.