Hidden pain in the anus may be caused by external hemorrhoids, anal fissure, sinusitis and other disease conditions. 1. External hemorrhoids: usually due to perianal venous thrombosis, perianal skin or subcutaneous tissue inflammation, perianal connective tissue hyperplasia and so on, and also with dietary habits, alcohol consumption, lifestyle and other factors. Generally simple external hemorrhoids without pain, but thrombosed external hemorrhoids and inflammatory external hemorrhoids patients, often appear painful symptoms, can also be manifested as anal hidden pain. Some patients can also be accompanied by anal swelling, itching, blood in the stool and so on. 2. Anal fissure: usually due to mechanical injury, anal canal pressure, infection and other conditions, but also with sexually transmitted diseases, AIDS, anal trauma, long-term constipation or diarrhea, mental tension and other factors. Patients can have cyclic pain, mostly during defecation, and gradually relieved after defecation, can also appear the phenomenon of vague pain in the anus. Patients can also be accompanied by constipation, blood in the stool, itching and so on. 3. Sinusitis: usually caused by bacterial infection, and often eat spicy, fried food and other factors. Generally chronic sinusitis patients with mild symptoms, mostly manifested as anal pain, anal canal falling sensation, some patients can also be no obvious symptoms. Acute sinusitis patients can appear anal swelling, anal canal falling sensation, pain, defecation and other symptoms, can also appear in the anal hidden pain. It is recommended that patients with symptoms of vague anal pain, timely medical treatment, and after clarifying the cause of the disease, to take reasonable treatment measures to avoid aggravation of the condition.