I have a ton of allergies. Food wise, the Big Three are peanuts, milk and eggs. I'm also allergic to pet dander and saliva (or so I've been told, anyway), dust, pollen, and all the usual airborne suspects. But it's those food allergies that are most crippling. I have to avoid a lot of foods because of them, and if I do eat something I'm allergic, it will affect me far worse than the other allergy triggers I have.
For the most part, my allergies manifest themselves as a constant red, itchy rash and hives that cover my body. Nasal/asthma symptoms are comparatively few and far between.