Emily, unfortunately, the allergic reaction you're suffering is because of the proteins shed by the mealworms and probably not the substrate. Many studies have been done showing that grain elevator workers suffering severe allergies at work are responding to the insects in the grain and not the grain itself. Darkling beetles from the family Tenebrionidae are notorious for stimulating allergic reactions (google "Tenbrio molitor allergy). Maybe you could use a mask and latex gloves when handling them to limit problems. I've known a few people that developed beetle allergies. I'm surprised I haven't yet developed one to them yet, it seems as I age I'm becoming allergic to just about everything.
Thanks Gallo for the info. I've been reading several websites about this and realised the seriousness of what is happening to me. I am on the verge of full blown asthma attacks so the mealies are going to have to go. I tried putting them out in the garage but it seems they starting to smell more. And everytime I go to the garage I have a reaction.....sooooooo!!! However, I am not just quitting on them right away. I am picking out, masked!!!, the full size worms and freezing them. I will let the babies grow up and pick them out as they grow.