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Salem Health: Infectious Diseases & Conditions, 2nd Edition

Anal abscess

by Amanda Barrett

Category: Diseases and conditions

Anatomy or system affected: Anus, gastrointestinal system, glands, rectum, skin

Also known as: Anal fistula, anal rectal abscess, anal rectal fistula, anorectal abscess, anorectal fistula

Definition

An anal abscess is a pus-filled glandular cavity near the anus, either deep in the rectum or close to the opening of the anus. Between eight and nine of every ten thousand persons will experience this condition.

Causes

An anal abscess results when bacteria infect a mucus-secreting gland in the anus or rectum, causing blockage and damage to surrounding intramuscular tissue. It is unknown why the infection occurs because, normally, this area is free from infection.

Risk Factors

The chance of developing an anal abscess increases for males and for persons with colitis or other inflammatory bowel disease, such as Crohn’s disease.

Symptoms

In the case of an abscess near the surface of the skin on the buttocks, the symptoms will include pain and tenderness radiating from the location of the abscess, visible redness and swelling, and fever. In the case of an abscess located deeper within the rectum, the symptoms will include pain in the lower abdomen, swelling in the rectum that can be seen during examination of the rectum, and fever. Furthermore, anal abscesses may be accompanied by pain with stool or stool incontinence (inability to restrain stools), or both.

Screening and Diagnosis

Although a doctor will be able to see an abscess near the surface of the skin, he or she also may need to examine the rectum with a gloved finger to determine the presence of a deeper abscess.

Treatment and Therapy

Treatment normally consists of draining the abscess, which is done by making an incision through the skin near the anus into the abscess. For this, a local anesthesia is administered. In rare cases, admittance to a hospital is required, and the patient might receive a general anesthesia. Antibiotics may be given to reduce fever or under other special circumstances.

Following drainage (or natural rupture) of an abscess, more than one-half the cases will develop into anal fistulas (usually occurring weeks but sometimes years later). In this condition, a permanent abnormal channel is formed from the site of the original abscess to the surface of the skin near the anus. This channel (fistula) allows for the continuous drainage of the abscesses’ puslike fluid. In the case of a fistula, surgery to remove and close the channel is normally recommended. Recurrence of a fistula is common, and stool incontinence may occur, after surgery.

Prevention and Outcomes

There are no known ways to prevent anal abscesses or subsequent fistulas because the cause of the original infection of the anal glands is unknown.

Further Reading

1 

“Abscess.” In Ferri’s Clinical Advisor 2011: Instant Diagnosis and Treatment, edited by Fred F. Ferri. Philadelphia: Mosby/Elsevier, 2011.

2 

“Abscesses.” In The Merck Manual Home Health Handbook, edited by Robert S. Porter et al. 3d ed. Whitehouse Station, N.J.: Merck Research Laboratories, 2009.

3 

American College of Gastroenterology. “Common Gastrointestinal Problems: Rectal Complaints.” Available at http://www.acg.gi.org/patients/cgp/cgpvol3.asp#rectal.

4 

EBSCO Publishing. DynaMed: Fistual-in-Ano. Available through http://www.ebscohost.com/dynamed.

Web Sites of Interest

American College of Gastroenterology

http://www.acg.gi.org

American Society of Colon and Rectal Surgeons

http://www.fascrs.org

See also: Abscesses; Bacterial infections; Boils; Men and infectious disease; Pilonidal cyst; Skin infections.

Citation Types

Type
Format
MLA 9th
Barrett, Amanda. "Anal Abscess." Salem Health: Infectious Diseases & Conditions, 2nd Edition, edited by H. Bradford Hawley, Salem Press, 2020. Salem Online, online.salempress.com/articleDetails.do?articleName=Infect2e_0029.
APA 7th
Barrett, A. (2020). Anal abscess. In H. B. Hawley (Ed.), Salem Health: Infectious Diseases & Conditions, 2nd Edition. Salem Press. online.salempress.com.
CMOS 17th
Barrett, Amanda. "Anal Abscess." Edited by H. Bradford Hawley. Salem Health: Infectious Diseases & Conditions, 2nd Edition. Hackensack: Salem Press, 2020. Accessed September 16, 2025. online.salempress.com.