An OAS reaction usually comes on swiftly and can recede just as quickly.
You’re sitting there eating and all of a sudden, your lips (or tongue and palate) begin to swell.
There might tingle or itch at the back of your throat, or you might start to sneeze, have the urge to blow your nose or rub your eyes because of tearing.
While that is usually the end of it, symptoms do cover the spectrum, from what looks like a fat lip all the way to vomiting, diarrhea and, on rare occasions, anaphylactic shock.
Who’s at Risk?
Those who have allergies to pollen from trees (such as birch and alder), and/or ragweed and grass pollen.
In Europe and Asia, those allergic to mugwort pollen, also commonly get symptoms to certain fruits, vegetables, spices and seeds.
See Also: Chart on Cross Reactors