Anal fissure may be caused by the following situations: first, anal fissure, most of them are due to recent bad dietary habits, so that the stool is too dry, hard, too hard to defecate so that the skin at the anal opening is torn, you will see obvious tearing wounds, accompanied by a strong sense of pain, after defecation will continue to bleed painfully for more than ten minutes, but the amount of bleeding is not much, plus itching in the affected area and other symptoms. Secondly, it may be fungal infection or bacterial infection leading to abnormal itching and pain in the local skin, and scratching makes the local skin crack. It can also not be ruled out is caused by anal fistula, the cause is more complex, timely to the hospital to do anal fingerprinting or anoscopy, diagnosis and symptomatic treatment.