Have Been Having Difficulty With Anal Itching And Burning Sensation.

Have been having difficulty with anal itching and burning sensation. Itching occurs after several closely spaced BM's. apparently caused by lactose intolerance. No bleeding, no nausea, no gas problem. Is this a potentially serious problem or just symptoms to be managed. Had stapled hemorrhoidectamy about 7 months ago. Itching has occurred in the last few months.