My dog Anna woke up one morning COVERED in hives. She was puking as well. I had used a washing liquid for a while for our clothes and she was ok, but the moment I washed her bed with it, she broke out bad. It took her a while to get better and we did use benadryl to help ease her itchiness, per vet recommendation, and he gave her some shots but she did get over it. I never used the same liquid, went back to our old stuff and it's never happened again.
I can't help but wonder if maybe it's not the brand of washing liquid you are using but maybe just the same ingredient in everything you are using. Have you tried not using anything at all but just plain hot water? If not, try washing all of her things several times in hot water to get rid of any residue left behind from any detergent. Vinegar is also a great, natural alternative to help getting rid of smells without using chemicals for her anal gland smell. Not ON her but on her things if they smell like anal glands. I hope she gets better and it seems like the stuff you are using is working!
I know you said you got her from a farm. I know that a lot of farms are devoid of grass with the machinery and animals trampling all over everything and they can be awfully muddy. Is it possible that she may be allergic to the grass or something IN the grass?