i have been taking erythromycin prescribed by my dermatologist and will be on it for a total of 6 weeks. when is started on the meds 3 weeks ago, severe anal itching began. i read that eating yogurt will help the itching go away, as the antibiotics have disturbed my colon ecology. but what is really going on? why the itching? is something trying to get out because that's what it feels like? needless to say, it is getting in the way of my routine and there's not much i can do for relief. any suggestions?