Anal swelling for four months may be related to hemorrhoids, proctitis, perianal abscess and other causes. 1. Hemorrhoids: soft venous masses caused when the varicose veins in the anus do not return smoothly. Due to the irritation of hemorrhoids, it can lead to swelling and falling sensation in the anus. In addition to this, it can also lead to symptoms such as prolapse of meatballs in the anus after bowel movement, painful sensation in the anus, and fresh blood during bowel movement. 2. Proctitis: It is an inflammatory disease formed when infected with bacteria or viruses. Inflammation can cause damage and irritation to the intestinal mucosa, which can lead to the symptoms of increased stool frequency, urgency and heaviness, which is manifested as bloating in the anus and often wanting to have a bowel movement. 3. Perianal abscess: usually caused by bacterial infection. This disease can lead to severe pain in the anus, warming of the perianal skin and a feeling of fluctuation. It can also lead to a feeling of swelling in the anus. 4. Other: diseases such as sinusitis, rectal prolapse, anal papilloma prolapse, etc., can also cause a swelling sensation in the anus. When the symptoms of anal swelling for a long time, it is recommended to go to the hospital specialist examination to clarify the cause of the disease, and then targeted treatment, so as not to delay the condition.