An anal abscess is a pus-filled lump that forms in the anus. This condition usually occurs due to a bacterial infection in the anal area. An anal abscess causes pain, especially when sitting or having a bowel movement.
An anal abscess is usually characterized by a small, reddish lump in the anal canal . In some cases, an abscess can also appear at the end of the large intestine that connects to the anus (rectum).
If not treated immediately, an anal abscess can cause the formation of an abnormal channel in the anus (anal fistula). This condition will make the pain worse, even causing difficulty controlling bowel movements.
Causes of Anal Abscess
An anal abscess occurs when the glands around the anus become infected with bacteria. As a result, the glands become enlarged and filled with pus. Some causes of an anal abscess include:
- Blockage of glands in the anus
- A wound or tear in the anus (anal fissure) that is infected
- Anal injury
- sexually transmitted diseases
Risk factors for anal abscess
Anal abscesses can happen to anyone, but this condition is more at risk for people who:
- Suffering from inflammatory bowel disease, such as ulcerative colitis and Crohn’s disease
- Suffering from pelvic inflammatory disease, diabetes, diverticulitis, diarrhea, or constipation
- Having a weak immune system, for example because you have HIV/AIDS
- Taking corticosteroid or chemotherapy drugs
- Having sex through the anus (anal)
- Smoke
Anal abscesses are also more likely to occur in pregnant women, as well as in babies and toddlers who are still wearing diapers.
Symptoms of Anal Abscess
A common symptom of an anal abscess is stabbing pain in the anus or rectum. This pain is continuous and gets worse when sitting, coughing, and having a bowel movement.
Other symptoms that may arise due to an anal abscess are:
- Constipation
- Body gets tired easily
- Difficulty urinating
- Fever and chills
- Pain in the lower abdomen
- Irritation, swelling, and redness around the anus
- Pus or blood discharge from the anus
When to see a doctor
See a doctor if you experience symptoms as mentioned above. An anal abscess that is left untreated can develop into an anal fistula, which is an abnormal channel that forms in the anus. An anal fistula must be treated with surgery and usually takes a long time to heal.
Go to the emergency room immediately if you have a high fever accompanied by vomiting, chills, difficulty defecating, and unbearable pain around the anus. These symptoms can indicate that the infection has spread to the bloodstream. If not treated quickly, the patient can experience sepsis, shock, and even death.
Diagnosis of Anal Abscess
The doctor will begin the diagnosis by asking about the patient’s symptoms and medical history. Next, the doctor will perform a physical examination of the patient’s rectal area. Through a physical examination, the doctor can distinguish whether the lump in the patient’s rectum is an abscess or hemorrhoids.
The doctor will also perform supporting examinations to determine the cause of the abscess that forms in the anus. These examinations include:
- Blood tests, to detect diabetes, inflammatory bowel disease or HIV/AIDS
- Endoscopy or colonoscopy, to see the condition of the anal canal and rectum.
- Ultrasound, CT scan or MRI scans, to detect deeper abscesses that are not visible during physical examination.
Anal Abscess Treatment
Anal abscess cannot be cured with antibiotics alone. The treatment that needs to be done to overcome this condition is surgery, the type of which depends on the location of the abscess.
If the abscess is located in a shallow area, the patient will undergo minor surgery and can usually go home after recovery. However, if the abscess is located deeper or is large, the patient will need to be hospitalized.
Anal abscess surgery can be performed under local or general anesthesia. The surgery is done by making an incision in the abscess area and draining the pus from the anus.
After surgery, the doctor will prescribe antibiotics to treat infections, and pain relievers, such as paracetamol. Patients are also advised to soak the anus in warm water or sitz baths 3–4 times a day.
To help the healing process, patients can eat soft foods and high fiber, and drink lots of water to facilitate bowel movements. Patients can also use stool softeners to relieve pain during bowel movements.
Complications of Anal Abscess
If left untreated or not routinely checked after surgery, an anal abscess can cause a number of complications below:
- anal fistula
- Persistent (chronic) pain in the area of the abscess
- Difficulty controlling bowel movements (fecal incontinence)
- Abscess recurrence after surgery
- Infection that spreads to the bloodstream (sepsis)
Prevention of Anal Abscess
There are several ways that can be done to prevent the formation of anal abscesses, including:
- Prevent sexually transmitted infections, one way is by using condoms during intercourse.
- Seek immediate treatment if you have a sexually transmitted infection.
- Treating diseases that can increase the risk of developing an anal abscess, such as diabetes and inflammatory bowel disease.
- No anal sex
- Maintain genital and anal hygiene
- Change your child’s diaper regularly
References:
Alabbad, J., et al. (2019). Retrospective Clinical and Microbiologic Analysis of Patients with Anorectal Abscess. Surgical Infections, 20(1), pp. 31–4.
Zheng, L., et al. (2018). Impact of Smoking on Anal Abscess and Anal Fistula Diseases. Chinese Medical Journal, 131(09), pp. 1034–7.
National Institutes of Health (2020). MedlinePlus. Anorectal Abscess.
Johns Hopkins Medicine (2021). Conditions and Diseases. Anorectal Abscess.
Cedars Sinai (2021). Health Library. Anorectal Abscess.
Ansorge, R. WebMD (2021). Anal Abscess.
Davis, C. Emedicine Health (2021). Anal Abscess.
Hebra, A. Medscape (2020). Anorectal Abscess.
Kennard, J. Verywell Health (2021). An Overview of Anal or Rectal Abscess.
Wint, C., Solan, M., & Wu, B. Healthline (2022). Anal (Rectal) Abscess: Everything You Need to Know.