On my first infusion of Remicade, it didn't give me hives, but it gave me the feeling of ants crawling under my skin all over, not exactly itching ... It happened during each of the 3 days afterward, at exactly the time the IV was started.... I'd take a Benadryl and it was gone in 10 minutes.  So - on the 2nd infusion, they put 100 mg of Benadryl.  Warning: if they do this, someone else should drive you home!  Even tho' they gave me coffee, it was a long 70 miles home...  so I decided Remicade was not for me, and switched to Enbrel.  It's been working well for 4 years with minor side effects.

     The IV Benadryl not only gets into your body faster, but is supposed metabolized faster because of that.  I overreact to almost all meds so don't take my example as typical.

I broke out in hives 10 days after my infusion of Remicade.  The doctor said he would try it one more time but if I broke out again I would have to switch to another medication.  I broke out all over my face and body.