What Is The Perianal Area?

Perianal Skin Can Be Easily Damaged, Especially After Diarrhea

Anorectal Fistula
In Crohn's disease, the lining of the intestine may ulcerate and form channels of infection -- fistulas. Fistulas tunnel from the area of ulceration, creating a hole which may continue until it reaches the surface of the organ, or that of nearby skin.. Photo © A.D.A.M.

Perianal refers the area of the body surrounding the anus, and in particular, the skin. The perianal skin is very sensitive and is susceptible to injury and damage from diarrhea, constipation, and disease.

Irritation to the perianal area can occur with persistent diarrhea. The diarrhea itself may be caustic and burn the skin, and repeated wiping with toilet paper can cause further trauma. Treating the diarrhea and then keeping the area clean and dry are important for healing the perianal skin.

Diseases And Conditions Of The Perianal Area

Diseases and conditions that can affect the perianal skin include:

  • External hemorrhoids: Hemorrhoids that occur on the outside of the anus that can be painful, itchy, and tend to bleed. Hemorrhoids can occur because of liver disease, constipation, diarrhea, or during pregnancy. Symptoms may get worse during a bowel movement. In many cases hemorrhoids will get better with home treatment, but in some cases they may need to be treated by a gastroenterologist or a colorectal surgeon. If a blood clot occurs, the hemorrhoid may become thrombosed, and cause more pain and swelling.
  • Crohn's disease: Crohn's disease can occur in any part of the digestive system, and the perianal area may also be affected. Approximately 24% of patients with Crohn's disease have disease in the perianal area. People with Crohn's disease may also have skin tags, hemorrhoids, or, in extremely rare cases, cancer in the perianal area. In many cases, a colorectal surgeon will need to be consulted in caring for patients who have such complications of Crohn's disease.
  • Perianal abscess: An abscess is a collection of blood and pus that can occur anywhere in the body, including the perianal area. People with inflammatory bowel disease (IBD), and especially those with Crohn's disease, are more at risk of developing a perianal. A perianal abscess may start after there is a tear in the anus, and some bacteria enters the body through the tear. The symptoms are swelling, pain, fever, and loss of bowel control. Abscesses in the perianal area are usually treated by draining them, and then antibiotics may be given.
  • Perianal fistula: An abnormal tunnel in the body between the skin and the rectum, a fistula can occur with either form of IBD. One potential complication of a perianal abscess is the development of a fistula in the area, which sometimes can become chronic. A fistula might also form after a trauma or as a complication of Crohn's disease, anal fissures, cancer, radiation therapy, actinomycoses, tuberculosis, or infection with Chlamydia. Symptoms include a break in the skin, swelling, pain, and drainage (either pus or stool) at the site. The treatment is surgery (fistulotomy) or placing a seton through the fistula. The seton is a thread that is tightened over time and eventually removed.

The Bottom Line

Pain, swelling, itching, or a lump or a bump in the anal area should prompt a visit to a doctor to determine what could be causing the problem. A physician will want to do a physical exam and potentially a rectal exam to see what's happening. This is especially true for people who have IBD, and in particular, Crohn's disease.

Complications in the perianal area can occur, but catching them early and seeking treatment can help prevent more serious outcomes. 

Treatment will depend greatly on the cause of the symptoms in the perianal area. For simple hemorrhoids, the treatment might be done at home, but for more invasive problems like a fistula or an abscess, outpatient surgery may be needed. For people with an underlying digestive disease, getting even simple issues under control quickly is going to be key to avoiding more extensive problems later. 

Sources:

Galandiuk S, Kimberling J, Al-Mishlab TG, Stromberg AJ. "Perianal Crohn Disease." Ann Surg. 2005 May; 241(5): 796–802.

Safar B, Sands D. "Perianal Crohn’s Disease." Clinics in Colon and Rectal Surgery. 2007;20(4):282-293.

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