How long does miconazole stay in the body?. I have an allergic reaction. I was taking amoxicilin for strep and I got a yeast infection on the sixth day, so I put a miconazole nitrate ovul in the night of the seven day and next morning I woke up with hives. It is incredibly itchy. My doctor request a blood test to check if I was allergic to penecilin, cause I told him I have taken miconazole before, but I was wrong, what I took two years ago was clotrimazol. He put me on steroids for the hives, Diflucan and finish the amoxicilin, which he was skeptical because my hives appeared on the 8 day of amoxicilin treatment. I just want to know how long miconazole can stay in my body, cause my whole body looks awful, it is itchy and I don t know any improvement in my first day with methylprednisolone but maybe I m very impatient. Help!