What Is It?

The anus is the muscular canal through which stool passes out of the body. In adults, the anus is about an inch and a half long, and it has a lining that contains blood vessels, sensitive nerve endings and six to eight small anal glands. This article describes four disorders that cause anal pain and irritation:

• Anal fissure — An anal fissure, also called an anorectal fissure, is a linear crack or tear in the skin of the anus. Most anal fissures happen when a large, hard stool overstretches the anal opening and tears the delicate anal skin. Less often, anal fissures develop because of prolonged diarrhea, inflammatory bowel disease or sexually transmitted diseases involving the anorectal area. Acute (short-term) anal fissures are usually fairly superficial and shallow, but chronic (long-term) anal fissures may extend deeper through the anal skin to expose the surface of underlying muscle.



• Anal abscess — An anal abscess is a tight, painful pocket of pus near the anus. Most anal abscesses are not related to other health problems and arise spontaneously, probably when bacteria or intestinal debris contaminate an anal gland, creating a site of infection under the skin. Currently in the United States, more than half of all anal abscesses occur in young adults between the ages of 20 and 40, and men are affected more often than women. Most anal abscesses are located near the opening of the anus but they can occur deeper and higher in the anal canal, closer to the lower colon or pelvic organs.



• Anal fistula — An anal fistula is an abnormal, narrow, tunnel-like passageway that connects the remains of an old anal abscess to the surface of the skin. Anal fistulas develop in about half of all anal abscesses that have drained. Sometimes, the opening of the fistula at the skin surface leaks a thick, foul-smelling liquid that has traveled from the depths of the old abscess. In other cases, the opening of the fistula eventually becomes plugged with draining debris, causing the old anal abscess to flare up again as a firm pocket of pus.



• Anal stricture — An anal stricture is a tight band of scar tissue that constricts the anal opening, interfering with the ability to pass stool comfortably. Anal strictures can be caused by radiation treatment for cancers located near the anal area, some sexually transmitted diseases, direct trauma to the anus or, rarely, surgery to remove hemorrhoids.

Although all four anal disorders cause some type of anal discomfort or pain, other symptoms vary, depending on the specific anal problem.

For anal fissure, symptoms may include:

• Pain in the anal area, often described as sharp, searing or burning, and usually triggered by a large, hard bowel movement
• Mild rectal bleeding, typically appearing as a small amount of bright red blood spotting or streaking toilet paper after a bowel movement
• Anal itch

For anal abscess, symptoms include:

• A firm, tender mass or swelling in the anal area, which may be so large that it pushes the anal opening to one side
• Throbbing pain near the anus that may worsen with walking
• Fever, chills and a generally sick feeling
• Pain in the lower abdomen, if the abscess is located high in the anus near the lower colon

For an anal fistula, signs and symptoms may include:

• Pain or discomfort around the anus, usually centered in an area where an old anal abscess has either drained spontaneously, or has been opened surgically by a doctor
• Persistent drainage of blood, pus or foul-smelling mucus from the anal area
• Symptoms of anal abscess (see above), which typically develop if the external opening of the fistula becomes clogged and the old abscess reactivates

For an anal stricture, symptoms include:

• Discomfort or pain during bowel movements
• Difficulty in passing stool because the anal opening feels too tight or too small

Once you have described your symptoms, your doctor will ask questions about your medical history and lifestyle that will help in evaluating your anal problem. Depending on your symptoms, the doctor may ask about:

• Your bowel habits, especially any history of constipation
• Your past medical history, including any history of bleeding disorders, episodes of rectal bleeding, inflammatory bowel disease, sexually transmitted diseases or radiation treatment for cancer
• Your use of prescription or nonprescription medications that may increase the risk of bleeding
• Whether you practice anal intercourse or have any history of anal trauma

Next, your doctor will perform a brief physical examination of your abdomen, followed by an external examination of your anal area and a digital rectal examination. If you have an anal fissure, no other tests may be necessary. However, for other anal disorders, your doctor may perform anoscopy (insertion of a tubelike instrument into the anus to look inside the anal canal).

The duration of anal disorders varies:

• Anal fissure — Painful anal fissures can be a recurrent problem in people who suffer from repeated episodes of constipation. Fortunately, superficial fissures usually heal quickly with medical treatment, and most symptoms disappear within a few days.



• Anal abscess — An anal abscess sometimes drains on its own, although it is always safer for a doctor to evaluate the problem. An anal abscess may develop into an anal fistula even with appropriate treatment.



• Anal fistula — Without treatment, an anal fistula may ooze blood or pus for prolonged periods. It will not heal on its own without surgery.



• Anal stricture — Once it develops, an anal stricture will not relax and open on its own. It must be treated by a doctor.

You may be able to prevent anal fissures by preventing episodes of constipation. To do this, soften your stool by gradually adding more fiber to your diet, and by drinking six to eight glasses of water daily. Begin a program of regular exercise. As little as 20 minutes of brisk walking each day may be enough to stimulate your bowel function. To help train your digestive tract to have a regular bowel movements, schedule a 10-minute period to sit on the toilet at approximately the same time each day. Also, never postpone having a bowel movement until the time is more convenient. Respond to the urge immediately.

Although it is not always possible to prevent other types of anal disorders, you may be able to decrease your risk for these illnesses by:

• Using gentle techniques to clean the anal area
• Keeping the anal area dry by changing underwear frequently and using powder to absorb moisture
• Always using a condom if you practice anal intercourse
• Never inserting any foreign object into the rectum

A doctor must diagnose the four anal disorders described here. Once the diagnosis is made, your treatment may or may not involve surgery, depending on the specific disorder. If surgery is necessary, your doctor will use whatever type of anesthesia is appropriate to prevent you from feeling pain in this very sensitive area.

• Anal fissure — For an acute fissure, your doctor may recommend that you use a stool softener and follow the suggestions for relieving constipation that are described in the Prevention section above. He or she also may tell you to apply a medicated cream to the fissure, and to soak the anal area in warm water for 10 to 15 minutes several times a day. For chronic fissures, surgery can correct the problem in more than 90 percent of cases.



• Anal abscess — An anal abscess must be opened by a doctor to drain the pus. This procedure is called incision and drainage, or I&D. This usually can be done as an outpatient procedure, especially if you are young and generally healthy, and your abscess is close to the anal opening.



• Anal fistula — Your doctor usually can remove an anal fistula in a surgical procedure called a fistulotomy, which also scrapes away any remnants of the old anal abscess.



• Anal stricture — If you have a mild anal stricture, your doctor may recommend that you use a stool softener or fiber supplement to help ease your bowel movements past the narrowed anal opening. If your stricture is more severe, your doctor will treat the problem either by carefully stretching (dilating) the anal opening with a special instrument, or by surgically cutting through the scar tissue.

Call your doctor promptly whenever you have rectal bleeding or any bloody discharge from the anus. Even if you have been treated for a bleeding fissure in the past, it is always safer for your doctor to determine the best course of action. This is especially true if you are over age 40, when there is an increase in the risk of rectal bleeding from colorectal cancer and other serious digestive diseases.

Also, call your doctor if you have:

• Severe pain in the anal area
• A tender mass or swelling near the anus, with or without a fever
• Pus or a foul-smelling discharge from the anus
• Discomfort or tightness in the anal area that interferes with bowel movements

In most cases, the prognosis is excellent. Almost all acute fissures heal quickly with conservative treatment, and almost all fistulas and chronic fissures can be corrected with surgery. Appropriate treatment of anal strictures will allow stool to pass easily and comfortably.

About half of all anal abscesses heal after being drained by a doctor, while the other half develop into anal fistulas. If a fistula does complicate the healing of an abscess, a fistulotomy will totally eliminate both the fistula and any remaining abscess in most patients.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.