There are many reasons for the swelling around the anus with itching: first, it may be a perianal abscess formed after the anal gland infection spreads along the anal canal to the perianal skin, and the fluctuation is usually more obvious to touch, and perianal ultrasound can make a clear diagnosis. Once diagnosed, surgical treatment, such as perianal abscess incision and drainage, should be performed in a timely manner. Secondly, it may be a sentinel hemorrhoid caused by anal fissure. Chronic anal fissure usually causes a triad of anal fissure, hypertrophic anal papilla and sentinel hemorrhoid, and over a longer period of time, the sentinel hemorrhoid will protrude outside the anus and form a mass with a soft texture. In this case, we should promptly perform surgical treatment, such as anal dilation or fissure removal. Thirdly, in case of external hemorrhoids, there may also be parametrial swelling, combined with infection or thrombosis, which may be accompanied by itching, and in this case, if combined with thrombosed external hemorrhoids, timely thrombectomy should be performed.