A small lump on the asshole may be a symptom caused by anal fistula, external hemorrhoids, eczema, warts and other diseases. Patients should go to the hospital in time, under the guidance of the doctor to clarify the cause of the disease. 1. anal fistula: anal fistula is an inflammatory infectious lesion that occurs in the patient’s anus, the patient may appear anal pimples and is accompanied by surface redness, swelling, secretion of mucus and other symptoms. 2. External hemorrhoids: external hemorrhoids are pathologic expansions caused by varicose veins in the lower anorectal region, resulting in the formation of masses. Therefore, external hemorrhoids can lead to small lumps in the anus, accompanied by itching, pain, bleeding in the stool and other symptoms. 3. Eczema: Eczema is an inflammation of the superficial dermis caused by a variety of factors, patients mainly appear single or groups of small pimples. Therefore, patients with perianal eczema may have the symptom of long pimples at the anus. 4. Condyloma acuminatum: Condyloma acuminatum, also known as genital warts, is a sexually transmitted disease, often caused by human papilloma infection. The patient can appear in the anus and genitals around the superfluous organisms. As a result, patients with warts may experience the symptom of a small bump growing on the anus. Patients who have a small bump on their asshole should go to the hospital in time, and under the guidance of the doctor for regular treatment.