 [ Symptoms ] on antibioticsinhaler for bronchitis soon after starting meds terribly itchy rash behind both knees drug allergy  started antibioticsinhaler tuesday rash presented wednesday morning rash is isolated to back of knees and has not changed in appearance or area currently using hydrocortisone and gold bond creams [ Disease ] hi the best thing you can do is google the drug and add side effects if one they have side effects like yours then it will be there good luck