I was on the new Oracea (doxycycline) for rosacea and I had taken it once a day for 12 days. On the 12th day my feet started itching and then before I new it I was itching all over. I wanted to crawl out of my skin! I got some hives as well and took Benadryl around the clock. The next afternoon I experienced crushing back and chest pain and thought I was having a hard attack! It got better the next day with less episodes and I felt better reading that other people also had these allergic reactions!