There is a small hard lump on the side of the anus, and it hurts a little bit when pressed. Consider the following possibilities: perianal abscess, hemorrhoids, sebaceous cysts, and anal fistula. 1. Perianal abscess: it is caused by bacterial infection in the perirectal space, and low-level perianal abscess is more likely. There will be the typical manifestation of redness, swelling, heat and pain, and the pain can be aggravated when pressed. 2. Hemorrhoids: hemorrhoids can be present in the anus of small lumps of flesh, but mostly soft lumps of flesh, but when the hemorrhoidal nucleus of blood vessels rupture bleeding, the formation of thrombus in its internal, can also be standard for small hard lumps, and pressure with pain. 3. sebaceous cysts: is the anus at the sebaceous gland conduit opening is blocked due to a complete capsule, the internal more tofu dregs-like material, hard. Usually there is no discomfort, some patients may have pain when pressing. 4. anal fistula: is a perianal abscess broken and healed after the formation of the anal side of the touch of the hard lump is considered to be a fistula or the outer mouth, when combined with inflammation can be painful when pressed. There is a small hard lump in the anus, pressing a little pain is also seen in other reasons, it is recommended that patients timely to the hospital, improve the auxiliary examination, in order to clarify the cause of the disease, the professional physician for the cause of the corresponding treatment, to avoid delays in the condition.