The old anal cramps and flatulence may be due to enteritis, hemorrhoids, sinusitis and other reasons. 1. enteritis: for example, bacterial dysentery, acute gastroenteritis and other diseases, will make the intestinal tract inflammatory reaction occurs, due to the stimulation of inflammation, can lead to intestinal peristalsis enhancement, increased gas production, so that the number of stools increased and the number of times of exhaust increased phenomenon. At the same time, due to the inflammation of the anus will produce stimulation, which will lead to the anus has a feeling of swelling. 2. Hemorrhoids: often accompanied by constipation, due to the feces for a long time in the intestinal tract, after fermentation, can produce a large amount of gas, which leads to the phenomenon of increased exhaust. At the same time, due to the narrowing of the space in the intestinal cavity, hemorrhoids stimulate the anus, which can lead to anal swelling symptoms. 3. Sinusitis: It is an inflammatory lesion that occurs in the anal crypt at the dentate line of the anus. This disease will lead to the emergence of anal swelling, pain, itching, increased exhaustion and other symptoms. When there is anal swelling and old gas, you should pay attention to light, avoid spicy and irritating food. At the same time, should also pay attention to perianal hygiene, adhere to the daily bath. If the symptoms are serious, it is recommended to go to the regular hospital as soon as possible, to clarify the cause of the disease, targeted treatment.