We thought my son had oral allergy syndrome because he's just started itching with cherries and melon. When he was in to see the allergist (he does have other food allergies), the allergist said, "Oh, no big deal, this is probably OAS (which is on the rise), but I'll test you." Sure enough, he has mild allergies to both cherries and melon now.

So, it's not ALWAYS OAS.