I had a cortisone injection into my left knee on Friday, June 5th...

I had a cortisone injection into my left knee on Friday, June 5th and immediately started to react. Within an hour, I had extreme redness and heat in my face, neck and upper chest. Wheezing, hives in throat and mouth and behind my ears. Extreme headache that came on suddenly and started in the back of my head and stretched to the front. Dizziness, chest discomfort. I went to the ER and was given a nebulizer treatment, benadryl IV and prednisone because the doctors at the ER felt that I must have had an allergic reaction to some medication that was mixed with the cortisone injection, because they said that to be allergic to cortisone is very rare. About 20 minutes after they gave me 60mg of oral prednisone, they started my benadryl IV. I felt such a hot rush to my face, my ears were burning. Eventually, the reaction calmed down and they sent me home with a prednisone taper and benadryl every 4 to 6 hrs. Sunday morning, I took 60mg of the prednisone and within 20 minutes I knew that I was in trouble so I took 50mg of benadryl and on the advice of my doctor, called an ambulance. In the ambulance, I was given oxygen, a nebulizer and more benadryl IV. After that morning, I knew that my problem was the steroid. I hadn't had any sleep since Thursday, I had been nauseous ands been battling chest discomfort and a very bad headache. I spoke with my doctor on Monday and he wanted me to take Atarax,25mg, every 3 to 4 hours. I saw him on Tuesday and I went to an allergist on Wednesday. She started me on 50 mg of zyrtec twica a day and 25mg of Atarax at night to see if this would help the reaction that I continue to have. She said that it could be several weeks, at least, that I will continue to react, until the injectable steroid is out of my system. It had been 13 days, and Im still reacting.