sinusitis
"Within 4 hours of taking the first dose of this medication my coxcyx began to itch, which was odd.  About six hours after taking the first dose I had terrible, intense, painful itching that was uncontrollable throughout my groin area including vaginal and anal itching. The more I scratched the more I itched. I tried Ice, and benedryl which helped a bit so I didn't go to the hospital.  In the morning the doctor changed the antibiotic and I  was  also given something to  successfully treat for the worst yeast infection I have ever had. Several years later I had the same experience (I forgot ) and now list cefdinir as a drug allergy. I am not allergic to any of Cefdinir's relatives, or penicillin."