Oral allergy syndrome or pollen food syndrome typically occurs among individuals who are allergic to pollen from grasses, trees or weeds. Take note that pollen from grasses, weeds and trees contain proteins that are similar in structure to those present in various fruits, nuts, vegetables and even spices. These proteins are recognized by the immune system as a threat, thus triggering the chemicals that are responsible for instigating the symptoms of an allergic reaction. This condition typically affects individuals who experience spring or summer hay fever but can also occur among those who do not have hay fever but test positive to pollen.
What are the common triggers?
Fresh fruit, raw nuts and raw vegetables are the common triggers of oral allergy syndrome. Some individuals are affected by only one or two foods and others can react to a variety of foods. The most common foods involved include peaches, apples, kiwi, almonds, hazelnuts but just about any fruit, nut or vegetable can cause a reaction.
Luckily, in most cases, the allergens are easily inactivated by cooking, processing and digestion. The symptoms tend to be limited to the mouth and throat and only manifest with raw vegetable or fruit. On the other hand, some react to both roasted and raw nuts.
Take note that soy milk can also trigger severe reactions in some individuals with oral allergy syndrome since it contains large amounts of protein which cross-reacts to birch pollen. Vegetables that are lightly cooked can also trigger reactions. Individuals who have oral allergy syndrome usually suffer from mild itchiness and/or swelling of lips, mouth, tongue or throat. On the other hand, this can occur occasionally severely and can also include vomiting and nausea. The symptoms typically start within minutes of eating and settle down within an hour.
What to do if oral allergy syndrome is suspected?
If an individual is suspected with oral allergy syndrome, it is vital to consult a doctor and if needed, an allergist should be consulted. This will ensure that a correct diagnosis is given as well as the appropriate treatment. The doctor will note down details of the reactions to decide whether there is evidence of a serious allergy and prescribe an epinephrine auto-injector.
As part of the diagnosis, a skin prick test is required. During the procedure, the skin is pricked after introduction of the allergen extract. Since fruit and vegetable allergens might be inactivated by processing, the testing involves prick testing instead of using the extract. If the individual is allergic, an itchy bump will appear within minutes after the test. Take note that it can be very itchy in the first few minutes, but will settle down over an hour. A blood test is not usually required if a skin prick test is available and might be less accurate.