if I had to guess I would call it an allergic reaction. allergic reactions can develop over time to meds that you might have taken previously without reaction. for example I was using Augmentin on a monthly rotating antibiotic therapy and I think the 3rd month of its rotation I developed an allergy to it. I would suggest calling doc and discussing alternatives.

dewy, i will see if i have it again tonight because i used the keflex today as experiment..i had this happen in past and never related to antibiotics so  not sure which ones caused it before either... and never stopped rotating the same  4 however...wondering if i do not have problem tonight if i can still continue on it..and why it would be inconsitant .but of course i will see what happens

you are however confirming my thoughts its the antibiotic.. however,my dilemma is i pretty much am using the only ones left i can use for pouchitis so hoping it could just come and go and i can continue to use it

do you or anyone else know if i did would that be a problem?

This is a tough one. Rashes and itching are common allergic responses to any antibiotic, and repeated exposure increases your risk of worsening reactions. Keflex probably causes more reactions than your other meds because of the cross sensitivity with penicillin (which we all know has a high rate of allergies). 

If you are really motivated to keep taking it (it really isn't the greatest for gut bacteria), there are a few things you can do. One is to see if you can get by with a lower dose. I take my antibiotics as a daily dose in the morning, so the blood level will be lowest at night. With Cipro and Flagyl this works for me, but Rifaximin I need to take twice a day when I take it. Often, sensitivities can be dose related. You can also try taking it with Benadryl (diphenhydramine) to reduce or prevent your reaction. 

Ultimately, you may just have to discontinue it.

Jan

thanks jan..i think i will try lowering dosage ..its high 500 mil three times a day ..maybe i can get by with two times a day 500 mil..and i need to see if i constantly  get itchy ever night on it i guess..will repot my findings in case anyone else has this problem..benedryl might work if i take with it..

Since the itching seems to come and go, it's also worth considering other (non medication-related) causes. Dry skin would be at the top of my list, at least with the winter weather we're having here.

Good point Scott. Also, drug rashes are usually on the trunk. But, I learned long ago to never say never (or always). I get dry skin eczema in the winter and it can drive me nuts. 

I have noticed more rashes when I'm on antibiotics. Been off for a week and it is clearing. 

Jan