See if it's the food. It's very easy to be or become allergic to mealworms, roaches, pretty much any of it. If she feels brave enough, expose her to them in a neutral location and see what happens. I've lost the ability to feed several insects now due to allergies.

Mine is mostly asthma but I have broken in hives many times.
It could be the UVB lighting, but she should be reacting to daylight as well if that's the case. There are certain medications that can make a person break out in a rash when exposed to sunlight,.
And yeah, she could actually be allergic to the chameleon. Anything that has protein chains (anything living) can create an allergic reaction in a person. I think it would be an extreme rarity though.
Has she ever been to an allergy doc and been tested? My family doc blamed my cats for everything and said I needed to rehome them all. When I finally went to a specialist they had to cut the prick test short - it should have taken 20 minutes and they had to scrub me down in 3 because my arms had doubled in size. I'm allergic to everything. He actually told me the cats were the least of my problems and not to bother getting rid of them. It was eye-opening, and it helped me avoid triggers and get treatment to slow the problem down. I highly suggest it to anyone having problems - because you might think it's one single thing but it could be a lot of things combined!