Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Anorectal fistula: Clinical manifestations, diagnosis, and management principles

Elizabeth Breen, MD
Ronald Bleday, MD
Section Editor
Martin Weiser, MD
Deputy Editor
Wenliang Chen, MD, PhD


An anorectal fistula is the chronic manifestation of the acute perirectal process that forms an anal abscess [1]. When the abscess ruptures or is drained, an epithelialized track can form that connects the abscess in the anus or rectum with the perirectal skin [2].  


The true prevalence of anal fistulas is unknown, as anorectal discomfort is often attributed to symptomatic hemorrhoids. The incidence of an anal fistula developing from an anal abscess ranges from 26 to 38 percent [3-5]. The mean age for presentation of anal abscess and fistula disease is 40 years (range 20 to 60) [6-9]. Adult males are twice as likely to develop an abscess and/or fistula compared with women [1,9].


The most common etiology of an anorectal fistula is an anorectal abscess. (See "Perianal and perirectal abscess".)

Other causes of anorectal fistulas include:

Crohn’s Disease – Fistulas complicating Crohn's disease or other intra-abdominal inflammatory processes may be accompanied by associated bowel symptoms such as diarrhea and abdominal pain. Anorectal fistulas preceding other clinical manifestations of Crohn's disease are uncommon. As an example, in one surgical series of 136 patients with Crohn's disease, fistulas preceded the intestinal manifestations of the disease in only six patients (5 percent) [10]. (See "Perianal complications of Crohn disease".)

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:

Subscribers log in here

Literature review current through: Sep 2017. | This topic last updated: Jun 08, 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Abcarian H. Anorectal infection: Abscess-fistula. Clinics in colon and rectal surgery 2011. 24:14.
  2. Whiteford MH, Kilkenny J 3rd, Hyman N, et al. Practice parameters for the treatment of perianal abscess and fistula-in-ano (revised). Dis Colon Rectum 2005; 48:1337.
  3. Ramanujam PS, Prasad ML, Abcarian H, Tan AB. Perianal abscesses and fistulas. A study of 1023 patients. Dis Colon Rectum 1984; 27:593.
  4. Scoma JA, Salvati EP, Rubin RJ. Incidence of fistulas subsequent to anal abscesses. Dis Colon Rectum 1974; 17:357.
  5. Vasilevsky CA, Gordon PH. The incidence of recurrent abscesses or fistula-in-ano following anorectal suppuration. Dis Colon Rectum 1984; 27:126.
  6. Piazza DJ, Radhakrishnan J. Perianal abscess and fistula-in-ano in children. Dis Colon Rectum 1990; 33:1014.
  7. Niyogi A, Agarwal T, Broadhurst J, Abel RM. Management of perianal abscess and fistula-in-ano in children. Eur J Pediatr Surg 2010; 20:35.
  8. Nelson RL, Abcarian H, Davis FG, Persky V. Prevalence of benign anorectal disease in a randomly selected population. Dis Colon Rectum 1995; 38:341.
  9. Sainio P. Fistula-in-ano in a defined population. Incidence and epidemiological aspects. Ann Chir Gynaecol 1984; 73:219.
  10. Nordgren S, Fasth S, Hultén L. Anal fistulas in Crohn's disease: incidence and outcome of surgical treatment. Int J Colorectal Dis 1992; 7:214.
  11. Goldberg JE, Steele SR. Rectal foreign bodies. Surg Clin North Am 2010; 90:173.
  12. Kurer MA, Davey C, Khan S, Chintapatla S. Colorectal foreign bodies: a systematic review. Colorectal Dis 2010; 12:851.
  13. Huang WC, Jiang JK, Wang HS, et al. Retained rectal foreign bodies. J Chin Med Assoc 2003; 66:607.
  14. Fry RD, Birnbaum EH, Lacey DL. Actinomyces as a cause of recurrent perianal fistula in the immunocompromised patient. Surgery 1992; 111:591.
  15. Coremans G, Margaritis V, Van Poppel HP, et al. Actinomycosis, a rare and unsuspected cause of anal fistulous abscess: report of three cases and review of the literature. Dis Colon Rectum 2005; 48:575.
  16. Rizzo JA, Naig AL, Johnson EK. Anorectal abscess and fistula-in-ano: evidence-based management. Surg Clin North Am 2010; 90:45.
  17. Anal abscess/fistula. American Society of Colon & Rectal Surgeons. 2008. www.fascrs.org/patients/conditions/anal_abscess_fistula/ (Accessed on April 25, 2011).
  18. Parks AG, Gordon PH, Hardcastle JD. A classification of fistula-in-ano. Br J Surg 1976; 63:1.
  19. Gupta PJ. Ano-perianal tuberculosis--solving a clinical dilemma. Afr Health Sci 2005; 5:345.
  20. Mathew S. Anal tuberculosis: report of a case and review of literature. Int J Surg 2008; 6:e36.
  21. Workowski KA, Bolan GA, Centers for Disease Control and Prevention. Sexually transmitted diseases treatment guidelines, 2015. MMWR Recomm Rep 2015; 64:1.
  22. Cirocco WC, Reilly JC. Challenging the predictive accuracy of Goodsall's rule for anal fistulas. Dis Colon Rectum 1992; 35:537.