Anal Abscess

A perirectal abscess is a collection of pus in the deep tissues surrounding the anus. By contrast, a perianal abscess is a shallower collection of pus under the skin surrounding the anus. Both types of abscesses need immediate attention. A delay in treatment may cause serious worsening of the condition and unnecessary complications.

Perirectal and perianal abscesses are thought to develop from the glands surrounding the anus. These glands may plug up, leading to infection. When they fill with pus, they may burst inward, releasing their infected contents into the spaces around the rectum and anus. This pus causes an abscess, or pus collection, in the spaces surrounding the rectum or anus. The anal abscess may enlarge, causing pain, fever, and difficulty with bowel movements.

Certain people are more likely to develop perirectal and perianal abscesses, including those with the following medical problems:

• Diabetes

• AIDS or HIV infection with low white blood cell counts

• Crohn disease

• Persons on medications that suppress the body's immune system, such as steroids (prednisone, methylprednisolone), or those undergoing chemotherapy for cancer

Signs and symptoms of perirectal and perianal abscesses include the following:

• Pain in the anal area or buttocks

• Fever

• A lump in the anal area

• Painful bowel movements

• Lower abdominal pain

• Fatigue

• Swelling in the anal area or buttocks

• Night sweats

If you suspect you have a perirectal or perianal abscess, see a doctor. The diagnosis is not always easy to make, and your doctor may need to do tests or consult with specialists.

Go to an emergency department when you have any of the following symptoms:

• High fever or shaking chills
  
  
• Significant pain
  
  
• Inability to have a bowel movement, or a painful bowel movement
  
  
• Persistent vomiting
  
  
• Any other unusual signs or symptoms that may indicate an emergency condition

See a doctor if you suspect that you have an anal abscess. She or he will ask questions about your condition. Give the doctor all necessary information. Discussing the details may be embarrassing, but to ensure your privacy, your doctor is required to maintain confidentiality. Your honest responses to your doctor's questions will help her or him to help you.

• The doctor will then examine you. She or he or will explain which parts of the exam may be uncomfortable and will be careful to protect your modesty.

• The doctor should provide clear answers to any questions you have, and you should understand the treatment plan.

• Sometimes the diagnosis is obvious, and no tests are needed. At other times, blood and urine tests and special imaging tests such as x-ray, CT scan, MRI, and ultrasound may be needed. The doctor may also consult other specialists to confirm the diagnosis or to come up with the best treatment plan.

|Self-Care at Home|

Both perirectal and perianal abscesses should be diagnosed and treated by a doctor. Do not delay seeing a doctor if you suspect you have a perirectal or a perianal abscess.

• A warm bath may help your symptoms.

• Nonprescription pain medicine, such as Tylenol, may help control the pain and fever.

• If the abscess opens by itself, there will be a release of pus and, possibly, some relief of pain and fever.

• Even if the symptoms improve with home care, you should seek medical attention. Abscesses need to be evaluated and treated by a doctor. They rarely go away on their own. Many people need further special treatment to avoid complications or a return of the abscess.

|Medical Treatment|

Depending upon the severity of the abscess and any other medical problems, treatment may be accomplished on an outpatient or inpatient basis. The treatment plan should be explained to you in detail.

• Minor surgery may be performed in the doctor's office or in the emergency department using local anesthesia (an injection in the infected area) and, possibly, IV sedation. You should be able to go home when you are awake and will be given prescription pain medicine for the first few days.

• Surgery may be done in the operating room by a surgeon using spinal anesthesia (you are awake and numb from the waist down) or general anesthesia (you are "asleep"). Your hospital stay may be overnight or several days.

• Admission to the hospital may be required with an IV line for fluids, antibiotics, and pain medicine.

• You may need an update of your tetanus booster, if this has not been done in the past 5-10 years.

• Blood and other tests may need to be repeated to evaluate your progress after treatment.

|Follow-up|

You may have pain for several days following surgery, but you should improve over time.

• You may not have stitches. Infected wounds such as abscesses are left open to drain. If they were stitched shut, they would just fill with pus again. There may be packing left in your wound, which will be removed by your doctor after a few days.

• You may need to take an antibiotic for several days, depending on your condition. You should be given strong pain medication if you need it.

• Using stool softeners and adhering to good hygiene, such as sitz baths after every bowel movement, decreases your discomfort and helps your recovery.

|Outlook|

Most perirectal abscesses and perianal abscesses can be successfully treated and cured. Some people have complications that require further testing and treatment. Allowing the abscess to go untreated may result in unnecessary complications and, in rare cases, death.

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Author: Drew E Fenton, MD, Emergency Physician, Department of Emergency Medicine, San Joaquin Community Hospital.

Editors: Steven C Gabaeff, MD, FAAEM, Attending Physician, Emergency Medicine, Sutter Amador Hospital, Jackson, CA; Expert Consultant, Medical Board of California, Sacramento, CA; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, ; James Quinn, MD, Director of Research Department of Medicine, Division of Emergency Medicine University of California at San Francisco Medical Center.