Anal swelling without blood in the stool is considered to be caused by proctitis, sinusitis, perianal abscess and other diseases. 1. Proctitis: caused by inflammatory bowel disease, infection, anorectal diseases and other causes, proctitis patients have a sense of urgency, that is, a feeling of anal swelling, frequent defecation but there is a sense of incomplete defecation, but also can be accompanied by abdominal pain, diarrhea and constipation alternating phenomena, may or may not be accompanied by blood in the stool symptoms. 2. Sinusitis: its cause is closely related to the anatomical structure of the anal sinus, clinical manifestations of incomplete defecation, anal swelling, anal itching and other phenomena, in severe cases, it can also involve the buttocks, perineum and other adjacent parts, thus causing urinary incontinence. 3. Perianal abscess: it is caused by purulent bacteria causing anal gland obstruction, infection and abscess formation, perianal abscess patients will appear around the anus small lumps, and can be sudden severe pain, deep abscess, but also can cause perineum, anus swelling. In addition, there are many other causes can cause anal distension without blood in the stool, it is recommended that patients go to the hospital in a timely manner, differential diagnosis, clear the cause of the disease, and receive treatment as soon as possible to avoid delays in the condition.