Itchy buttocks may be caused by perianal eczema, pinworms, hemorrhoids and other diseases. 1. Perianal eczema: it is an inflammatory reaction of the skin around the anus caused by a variety of internal and external factors. Often manifested as perianal papules or redness, hyperpigmentation, accompanied by intense itching, etc., which can cause itchy buttocks. 2. Pinworms: a common parasitic disease caused by helminths parasitizing the intestinal tract. Mainly manifested as itching around the anus and perineum, especially at night, which can also cause itchy buttocks. 3. Hemorrhoids: a common anorectal disease, is a swelling of the veins in the anus and rectum. The main manifestations are blood in the stool, itching and pain around the anus, anal swelling and other symptoms. It can also cause itchy buttocks. There are many other causes of itchy buttocks, and you should seek medical attention to identify the cause and follow medical advice for further treatment or therapy.