Perianal Abscess Underlying Cause
Perianal abscesses are caused by bacteria that are normally present on the surface of the skin around the anus. The bacteria become trapped in sweat glands or hair follicles, or enter the tissue beneath the skin when the skin becomes irritated. When the bacteria start to grow, the body forms an abscess to fight the infection.
Causes of irritation to the skin around the anus include:
- Festen C, van Harten H. Perianal abscess and fistula-in-ano in infants. J Pediatr Surg. 1998 May;33(5):711-3. 
- Murthi GV, Okoye BO, Spicer RD, Cusick EL, Noblett HR. Perianal abscess in childhood. Pediatr Surg Int. 2002 Dec;18(8):689-91. 
- Whiteford MH, Kilkenny J 3rd, Hyman N, et al; The Standards Practice Task Force; The American Society of Colon and Rectal Surgeons. Practice parameters for the treatment of perianal abscess and fistula-in-ano (revised). Dis Colon Rectum. 2005 Jul;48(7):1337-42.