I have been taking synthroid and cytomel for years now. Had hype...

I have been taking synthroid and cytomel for years now. Had hyperthyroidism (Grave's disease), had radioactive iodine treatment to leave me without a thyroid. About 6 months ago, I started getting hives. Doctors at first thought it was stress. I am not allergic to anything. The only medicines that I take on a regular basis are synthroid and cytomel. I think it might be because of these drugs but not sure. I have made an appointment to see my internist.