There is a bar-shaped lump in the skin on the left side of the anus, which may be caused by hemorrhoids, perianal abscesses, cysts or tumors. 1. hemorrhoids: mainly due to poor circulation in the anus, venous reflux obstruction caused by the left side of the anus may lead to the skin of the anus has a bar-shaped hard lump. 2. Perianal abscess: a purulent infection formed by bacterial infection of the perianal space, which may also lead to a strip of hard lumps in the skin on the left side of the anus. 3. Cysts or tumors: local cysts or benign tumors, malignant tumors and other occupying diseases, may also cause a strip of hard lumps in the skin on the left side of the anus. There is a bar-shaped hard lump in the skin on the left side of the anus, there may be other reasons, such as anal fistula and other diseases, it is recommended that the patient first go to the hospital for examination, differential diagnosis, follow the doctor’s instructions to give reasonable treatment to avoid aggravation of the condition.