Why do you get perianal abscess and anal fistula. 1. Anatomical factors. Newborns and infants have short anal canals, loose anal sphincter muscles, and delicate skin and mucous membranes, which can be easily infected by rough diapers or toilet paper abrasions. 2, the intestinal physiological function is not complete. Infants are prone to diarrhea, and feces and urine impregnation can easily induce infection. 3.Low immunity. If a perianal abscess does not heal for a long time, it can develop into an anal fistula. How to determine if you have perianal abscess? A perianal mass, redness and swelling, hard nodules, and a child crying when touched. How to treat? 1.Simple perianal abscess can be cut and drained first, slowly change the medicine, potassium permanganate (1:5000) warm water sitz bath, healing time is long, easy to recur. 2, long-term non-healing with anal fistula formation can be performed hanging therapy, fast recovery, low recurrence rate, less pain. 3.Fistula removal.