Hemorrhoids are clusters of swollen veins in and around the anal canal that may cause itching, and at times, severe pain. You may be referred to a surgeon if your hemorrhoids suddenly become thrombosed, or blocked with a blood clot, causing severe pain. Other indications to see a surgeon might be for chronic irritation, such as itching, burning or bleeding. Some hemorrhoids can be treated in the office with a procedure called banding. This is commonly performed on hemorrhoids that bleed and that are high up in the anal canal where the tissue does not have nerve supply. In some cases, hemorrhoids need to be treated surgically, which can be done at the hospital or at an outpatient surgery center.