Our allergist has us use antihistamines during any type of environmental allergen season, but hasn't ever suggested it *directly* for food allergies. OTOH, our dd has both food and environmental allergies, and our allergy drs believe in the concept of an immune "bucket" - basically your body can handle dealing with allergens up to a certain point, but when the bucket is "full" it's going to overflow and you'll see heightened and increased numbers of reactions - hence it's important to keep the bucket at "low level" - i.e., deal with what you *can* deal with, such as taking a daily antihistamine to keep the environmental allergens down, and in turn, that helps keep allergic reactions down overall.
To be honest, this jmo, but if you're a parent who's feeling that they need to give your child an antihistamine daily for any type of allergic reaction / hives / etc / whatever the source - I'd think that's a sign that you'd benefit from taking your child in to see an allergist. Especially since you have the note about sensitivities etc. What you're seeing during the winter might be something as simple as dust mite reactions, or it might be food, or it could really be anything. My dd with multiple food and environmental allergies is also allergic to changes in temperature when she comes in from the cold - and I would have had absolutely no idea that this has the possibility of being an anaphylactic type of allergy if she hadn't been under the care of a dr experienced in dealing with allergies.
Quantum, I realize your ds is already under the care of medical specialists for other issues, but it sounds like a trip to an allergist might be enlightening.
And yes, we use oral antihistamines to treat mild allergic reactions such as hives - for reactions due to environmental allergens and due to food allergens.
I hope that made sense - it was written in a hurry!
Best wishes,
polarbear
