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Itching of the anus and the skin around the anus (perianal skin) is called anal itching or pruritus ani.
Causes
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.
Evaluation
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.
Warning signs:
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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| Causes and Features of Anal Itching |
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Cause
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Common Features*
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Tests
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Anal or rectal disorders
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Inflammatory bowel disease (such as Crohn's disease)
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Discharge of pus
Pain in the rectum (sometimes) and/or abdomen (often)
Sometimes diarrhea
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Examination of the lower portion of the large intestine, the rectum, and the anus with an endoscope (sigmoidoscopy) or of the entire large intestine (colonoscopy)
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Hemorrhoids (internal or external)
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With internal hemorrhoids, bleeding (a small amount of blood on toilet paper or in the toilet bowl)
With external hemorrhoids, a painful, swollen lump on the anus
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A doctor's examination
Usually examination of the rectum with an endoscope (anoscopy) or sigmoidoscopy
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Infections
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Bacterial infection (caused by scratching)
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Inflamed, red area, sometimes visible scratching
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A doctor's examination
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Yeast infection (Candida)
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A rash around the anus
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A doctor's examination
Sometimes examination of a sample of skin scrapings under a microscope (to identify the fungus)
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Pinworms
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Usually in children
Sometimes present in several family members
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Microscopic examination of transparent tape that was applied to the anal area to check for pinworm eggs
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Scabies
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Intense itching, usually worse at night
Possibly itching of other body areas
Possibly pink, thin, slightly raised lines or bumps (burrows) on the affected areas
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A doctor's examination
Examination of skin scrapings
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Skin disorders
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Atopic dermatitis
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An itchy, red, oozing, and crusty rash
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A doctor's examination
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Psoriasis
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Sometimes itchy or painful patches on the skin
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A doctor's examination
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Drugs
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Antibiotics
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Current or recent use of an antibiotic
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Elimination of the drug to see whether symptoms are relieved
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Foods and dietary supplements
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Beer, caffeine, chocolate, hot peppers, milk products, nuts, tomato products, citrus fruits, spices, or vitamin C tablets
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Symptoms that occur after a substance is ingested
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Elimination of the substance from the diet to see whether symptoms are relieved
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Hygiene-related problems
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Excessive sweating
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Excessive sweating described by the person, particularly with wearing of tight and/or synthetic clothing
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Measures to limit sweating (such as wearing loose cotton underwear and changing underwear frequently) to see whether symptoms are relieved
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Overly meticulous or aggressive cleansing of the anal area
Poor cleansing
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Inappropriate cleansing practices described by the person
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A change in cleansing practices to see whether symptoms are relieved
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Skin irritants
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Anesthetic preparations, ointments, soaps, and sanitary wipes
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Use of a possibly irritating substance described by the person
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Avoidance of the substance to see whether symptoms are relieved
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*Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present.
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Testing:
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.
Treatment
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.
Key Points
Last full review/revision May 2012 by Parswa Ansari, MD
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