Anus long a hard thing may be thrombosed external hemorrhoids, perianal abscess, sebaceous cysts and other disease causes. 1. thrombosed external hemorrhoids: when the hemorrhoidal mass of external hemorrhoids occurs acute thromboembolism, in addition to causing severe pain in the perianal area, it can also lead to changes in the texture of the hemorrhoidal mass, so that it becomes more and more hard, which leads to the emergence of the sensation of having a hard hard thing at the entrance of the anus. 2. Perianal abscess: usually caused by the gradual aggravation of sinusitis. Perianal abscess is an abscess located in the subcutaneous space around the anal opening, and the disease will lead to symptoms of holding and obvious pain at the anal opening. At the same time, when touching the anal opening, in addition to obvious tenderness, you can also touch the anal opening there is a hard thing. 3. Sebaceous cysts: When the sebaceous ducts in the anal opening are blocked, it will easily lead to the formation of retention cysts (i.e. sebaceous cysts). This in turn leads to the appearance of spherical, acne-like, hard things at the anal opening. When the anus grows a hard thing, there may be other factors caused by, such as anal warts, anal fistula, etc. to observe its condition; at the same time should avoid fatigue, pay attention to local hygiene; if the symptoms are serious, it is recommended to timely examination and treatment, so as not to aggravate the symptoms and delay the condition.