Itching of the anus and the skin around the anus (perianal skin) is called anal itching or pruritus ani.
The most common causes of anal itching are
Most often, doctors do not identify a specific disorder as the cause of anal itching, and the itching goes away without treatment after a period of time. Many of the other cases of anal itching are due to hygiene issues. Only a very few cases are caused by a specific disorder (Table 1: Anal and Rectal Disorders: Causes and Features of Anal Itching), such as pinworms or a fungal infection. Of the specific causes, only inflammatory bowel disease or anal cancer (rare causes) is considered serious.
Extremes in hygiene can lead to anal itching. For instance, inadequate cleansing leaves irritating stool and sweat residue on the anal skin. More commonly, overly vigorous cleansing, often with sanitary wipes and strong soaps, can dry or irritate the skin or occasionally cause an allergic reaction. Hemorrhoids (see Anal and Rectal Disorders: Hemorrhoids) can make it difficult for people to thoroughly clean themselves after a bowel movement. Some hemorrhoids produce mucus or cause stool leakage, both of which can cause itching.
Once anal itching starts, an itch-scratch-itch cycle can begin, in which scratching causes more itching. Often, people scratch and rub the itchy area so much that they scrape the skin open. The scrapes sometimes become infected, which causes yet more itching. Also, people sometimes become allergic to the ointments or other treatments they use for the itching.
Not every episode of anal itching requires immediate evaluation by a doctor. The following information can help people decide whether a doctor's evaluation is needed and help them know what to expect during the evaluation.
In people with anal itching, certain symptoms and characteristics are cause for concern. They include
When to see a doctor:
People who have anal itching plus bloody diarrhea or draining pus should see a doctor in a day or two. Other people should see a doctor if the itching has lasted for more than a few days, but the visit is not urgent.
What the doctor does:
Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of the itching and the tests that may need to be done (see Table 1: Anal and Rectal Disorders: Causes and Features of Anal Itching).
The history is focused on when the itching started and how long it has lasted. Doctors ask about the following:
The physical examination is focused on the appearance of the anus and the perianal skin. Doctors examine this area for
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If doctors do not see any abnormalities on or around the anus, they usually do not do tests and simply treat the person's symptoms. If there are any visible skin abnormalities, doctors may examine a scraping of the perianal skin to rule out a fungal infection. Sometimes, they give the person a local anesthetic and remove a small piece of tissue to examine under a microscope (skin biopsy). If pinworms are suspected, eggs can be collected from the anal region using sticky transparent tape to confirm the diagnosis (see Parasitic Infections: Symptoms and Diagnosis).
Doctors may also examine the rectum with a short, rigid tube (a procedure called anoscopy) to check for internal hemorrhoids.
The best way to treat anal itching is to treat the underlying disorder. For example, drugs can be taken for parasitic infections, and creams can be applied for fungal infections. Irritating foods can be eliminated from the diet or avoided for a while to see whether the itching lessens. If possible, antibiotics can be stopped or switched.
Proper hygiene is important. After bowel movements, the anal area should be cleaned with absorbent cotton or plain soft tissue moistened with warm water or a commercial cleanser made specifically for hemorrhoids. People should avoid using soaps and premoistened wipes. Frequent dusting with nonmedicated cornstarch or talcum powder helps combat excess moisture. Corticosteroid ointments (such as 1% hydrocortisone) often help relieve symptoms. Clothing should be loose, and bed clothing should be lightweight.
Last full review/revision May 2012 by Parswa Ansari, MD