Anal abscess
An anal abscess is a pus-filled cavity that forms near the anus, either deep within the rectum or close to the anal opening. It typically occurs when bacteria infect and block a mucus-secreting gland in the anal region, leading to inflammation and damage to surrounding tissues. This condition affects about 8 to 9 individuals per 10,000 and can result from various factors, including inflammatory bowel diseases, sexually transmitted infections, and a weakened immune system. Symptoms may vary depending on the location of the abscess, with common signs including pain, tenderness, fever, and visible swelling. Diagnosis often involves a physical examination and may include imaging techniques to assess deeper infections. Treatment primarily involves draining the abscess, which can be done under local anesthesia, though some cases may require hospitalization. Following drainage, there is a risk of developing an anal fistula, an abnormal channel that allows continuous pus drainage. Preventative measures include maintaining good hygiene, addressing underlying health issues, and practicing safe sex. Understanding anal abscesses can help individuals recognize symptoms early and seek appropriate care.
Anal abscess
- 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 the surrounding intramuscular tissue. The infection can occur for several reasons, including blockage of the anal glands, weakened immune system, sexually transmitted infections, or inflammatory bowel disease.
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. Other risk factors include contracting a sexually transmitted infection and having a weakened immune system. Individuals with diabetes, diverticulitis, and hidradenitis suppurativa may also be at increased risk. Patients who have been on corticosteroids for an extended period also have an increased risk of developing anal abscesses.
Symptoms
In the case of an abscess near the skin surface on the buttocks, the symptoms will include pain and tenderness radiating from the location of the abscess, visible redness and swelling, fatigue, chills, 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, and fever. Rectal bleeding, difficulty urinating, and foul discharge are additional symptoms. 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 can see an abscess near the skin's surface, they may also need to examine the rectum with a gloved finger to determine the presence of a deeper abscess. Far more comprehensive methods of screening and diagnosing anal abscesses are also available. Imaging techniques like computed tomography, magnetic resonance imaging, and endoscopic ultrasound can offer interior pictures. Blood tests and procedures such as proctoscopy and anoscopy may also be employed.
Treatment and Therapy
Treatment usually 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 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 of 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.
Alternative treatment methods also exist and can be less invasive. Needle aspiration can drain pus from the abscess, or a small catheter can be placed in the abscess to allow for drainage. Sitz baths, stool softeners, and over-the-counter pain relievers are also recommended.
Prevention and Outcomes
Anal abscesses or subsequent fistulas can be prevented in several ways. Individuals should assess any underlying health conditions that may weaken the immune system and increase abscess frequency. Maintaining good personal hygiene and using safe sex practices are also ways to avoid anal abscesses. Preventing constipation and treating abscesses and fissures immediately are also preventive methods.
Bibliography
"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.
"Anorectal Abscess." Johns Hopkins Medicine, www.hopkinsmedicine.org/health/conditions-and-diseases/anorectal-abscess. Accessed 8 Oct. 2024.
Ferri, Fred F., editor. Ferri’s Clinical Advisor, 2024. Elsevier, 2023.
Wechter, Debra G., David C. Dugdale, and Brenda Conaway. "What Is Anorectal Abscess?" Penn Medicine, 20 Apr. 2022, www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/anorectal-abscess. Accessed 8 Oct. 2024.