Rye - what's it in besides rye bread?

Rye bread includes water, yeast, sugar, flour, salt, honey, an egg white, and of course rye flour. (but people can get fancy with variations). But that is not necessarily the store bought reciple. It is very possible that your son is allergic to ry However, keep in mind, sometimes a food allergy is not to the actual food item but to the chemicals that surround it. Just like some people with dairy allergies can actually eat organic dairy because its all the antibiotics in it that they actually react to. A soft, store bought bread is going to have an arm's length list of ingredients, including perhaps partially hydrogenated oils and more to keep it nice for weeks. And anywhere you see "natural spices" - that can be anything at all. If your son is not deathly allergic - but just mildly allergic, i may try to make rye bread with a breadmaker at home and see how he does. If he has no reaction, then its all the additives, not rye.