Hi, I had the same reaction to Keflex,an anti-biotic. Started a few days after I stopped taking the med. Ended up in the ER, they gave a shot of something which stopped the itching but I was really nervous from that shot for about 5 days. I was told not to take any penicillen drugs or sporins. I took penicilen all my life without a problem.
I itched the same way, my entire body. You do not have enough hands to scratch. I went to the ER. because my throat felt like it was closing, I do get hives, but had none or a rash.
Linda