10 years ago, I was diagnosed with Hypothyroid and placed on Synthroid. About 4 days later, I had hives on the palms of my hands, bottoms of my feet, the knuckles of my fingers and toes, hives on my elbows and knees and the most intense joint pain ever. Not to mention my scalp was about to itch off. Went to the ER and the doctor that night said I was allergic to the FD&C Yellow dye, so they put me on a different pill and all is well. (Although over the past 10 years, the Yellow Dye allergy has progressively gotten worse and I've had to change my soap, shampoo, and watch foods/beverages closely); however, the reactions to the Dye since the initial "Hives" reaction, has simply been a very reddening skin rash (of course, it hasn't built in my system for days like it did initially).

Fast forward 10 years, On September 15, I begain taking Bupropion Hydrochloride Extended-Release 100mg Tablets. On the 22nd, my scalp started itching. The morning of the 23rd, I noticed a hive on the palm of my hand. By that evening, my waistline, and elbows were covered in hives (I stopped taking the meds the morning of the 23rd when I saw the first hive). Yesterday (the 24th), I was itching very badly, my hands were swelling and they were very red. I had a conference that I could NOT miss. By the time I got home last night at 6:30, my feet were completely swollen and the bottoms of my feet were covered in hives and I couldn't walk. The pain in my joints was horrible. Off to the ER for the benedryl, epinephrine, and steroid shot.

My question is - what is it in these drugs that cause this type of reaction? I cannot go through this again!!!

Thanks so much for any tips or adivce or answers you can give me!!!