There are many anal and rectal lesions that can cause the anus to feel like a worm is wriggling inside. First of all, the most common is parasitic infection, mostly pinworm disease, the main reason is usually do not pay attention to the diet and hygiene after the stool, resulting in pinworm parasites in the intestinal tract, and cause the patient to appear abdominal pain, diarrhea, as well as itching in the anal area. Secondly, hemorrhoids caused by the symptoms of anal itching, hemorrhoids appear mainly due to varicose veins around the anus, especially in the anal canal dentate line above the internal hemorrhoids, because the hemorrhoidal nucleus edema or enlargement, stimulation of the rectal mucosa leading to the emergence of itching phenomenon in the anus. In addition, sinusitis can also lead to itching like worms in the anus, due to bacterial infection and fecal stimulation of the sinuses, resulting in inflammation and edema of the sinuses, which triggers itching in the anal area.