Nassif Share Your Story Education. Pain during bowel movements that can be severe Pain after bowel movements that can last up to several hours Bright red blood on the stool or toilet paper after a bowel movement Itching or irritation around the anus A visible crack in the skin around the anus A small lump or skin tag on the skin near the anal fissure Causes and Risk Factors Most often anal fissures are caused by trauma to the skin around the anus or the tissue lining the anus. Because anal fissures are often associated with other issues such as constipation and diarrhea, treating those issues can be the first step in treating the anal fissure. If the above treatments are unsuccessful or the fissures recur, your doctor may recommend surgery of the anal sphincter muscle to reduce spasm and pain and promote healing. Your doctor will start with a complete medical history to determine the frequency and duration of your symptoms.