Tingling, itching or swelling after vegetables, fruit or nuts
Does your mouth tingle after eating kiwi or pineapple? Or does a bite of an apple cause itching and swelling of your lips and tongue? There is a good chance that you suffer from Oral Allergy Syndrome (OAS). And the special thing is: apple pie or grilled pineapple usually does not cause any complaints.
OAS is common, especially in older children and adults. It is an allergic reaction that occurs after contact with raw vegetables, fruits or nuts. The symptoms are itching, tingling, a prickling sensation or swelling of the lips, tongue, mouth or throat. The symptoms come on quickly: within minutes. The reaction usually disappears within an hour.
Oral Allergy Syndrome and Hay Fever
OAS is common in people with hay fever. Hay fever causes an allergic reaction after inhaling pollen. Your body then makes antibodies against the proteins in the pollen. Unfortunately, the antibodies against pollen protein can also react to dietary proteins. The proteins in pollen and some foods are very similar. The proteins that cause a reaction are called allergens. For example, the apple allergen is so similar to the allergen of the birch, that an allergic person often reacts not only to the birch, but also to the apple. This is also known as a cross allergy. The chance that you as a hay fever patient will develop OAS is therefore high: about 50 to 90 percent of people with a tree pollen allergy develop a cross-allergy to pome and stone fruits (apple, cherry, pear, peach), nuts (almond , hazelnut), legumes (peanut, soy) or some vegetables (celery, carrot). A grass pollen allergy can lead to cross-allergy with stone fruits, melons and citrus fruits.
More complaints with a ‘pollen peak’
Most OAS symptoms occur in people who are also allergic to birch, alder, ragweed, mugwort, timothy grass and pollen grass. If there is a lot of pollen floating around from the tree/plant to which you are allergic, you also have a higher chance of OAS. For example, birch trees spread their pollen between January and April. If you have an allergic reaction to those pollen, there is a greater chance that you will develop OAS complaints during those months. For example, the pollen season for ragweed is in the summer and autumn and the chance of OAS complaints is greater if you cannot tolerate ragweed.
No apple, but applesauce
Never again hazelnuts or apple because they make you itchy? Maybe you can eat a raw apple or a handful of raw hazelnuts outside the pollen season. Do you still suffer from tingling or itching or do you want to eat something during the pollen season? Then it is good to know that the proteins that cause a reaction cannot withstand heat well.
There are two types of allergens: stable allergens and non-stable allergens. Stable allergens are not destroyed by heating. They reach the gastrointestinal tract intact and can cause an allergic reaction in the body. Unstable allergens break down if they are heated enough, so that an allergic reaction is no longer possible.
OAS involves unstable allergens. That is very nice, because after heating there is no longer an allergic reaction. That is why someone with OAS often cannot eat a raw apple or raw nuts, but can have a slice of apple-nut pie. Applesauce or pineapple from the barbecue, for example, also goes well.
If the symptoms are worse
Complaints of OAS usually do no harm and disappear on their own, at most they are just as annoying. But an allergy can also cause shortness of breath or a tight feeling in the throat. Do you not trust it or do you get very stuffy? Then call your GP or 112 in serious cases.
