Itching of the anus (the opening at the end of the digestive tract where stool leaves the body) and the skin around the anus (perianal skin) is called anal itching or pruritus ani.
(See also Overview of the Anus and Rectum.)
Causes of Anal Itching
The most common causes of anal itching are
Unknown (the majority)
Related to hygiene
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 (see table Causes and Features of Anal Itching), such as pinworms or a fungal infection. Of the specific causes, only rare causes such as inflammatory bowel disease and cancer of the skin around the anus are 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 can make it difficult for people to thoroughly clean themselves after a bowel movement. Some hemorrhoids produce mucus or cause leakage, both of which can cause itching.
Young children and older people may have problems controlling their urine (called urinary incontinence) or stool (called stool incontinence in children and fecal incontinence in adults). These disorders may cause irritation that leads to skin infections and anal 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 irritated, which causes yet more itching. Also, people sometimes become allergic to the ointments or other treatments they use for the itching.
Evaluation of Anal 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.
Warning signs
In people with anal itching, certain symptoms and characteristics are cause for concern. They include
Pus draining from the anus or around it (draining fistula)
Bloody diarrhea
Bulging or protruding hemorrhoids
Perianal skin soiled with fecal material
Dull or thickened perianal skin
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 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:
Ingestion of irritating foods, particularly acidic or spicy foods
Bowel habits, including use of wipes, ointments (even those used to treat itching), sprays, and soaps applied to the anus
Hygiene habits, particularly frequency of showers and baths
Known infections or disorders (such as diabetes, hemorrhoids, or psoriasis)
Recent use of antibiotics
The physical examination is focused on the appearance of the anus and the perianal skin. Doctors examine this area for
Dullness and thickness
Signs of irritation due to scratching
Hemorrhoids, lesions, fistulas, and scrapes (caused by scratching and rubbing)
Causes and Features of Anal Itching
Cause | Common Features* | Tests |
|---|---|---|
Anal or rectal disorders | ||
Inflammatory bowel disease (such as Crohn disease) | Discharge of pus Pain in the rectum (sometimes) and/or abdomen (often) Sometimes diarrhea | 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) |
Hemorrhoids (internal or external) | 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 | A doctor's examination Usually examination of the rectum with an endoscope (anoscopy) or sigmoidoscopy |
Infections | ||
Bacterial infection (caused by scratching) | Inflamed, red area, sometimes visible scratches | A doctor's examination |
Yeast infection (Candida) | A rash around the anus | A doctor's examination Sometimes examination of a sample of skin scrapings under a microscope (to identify the fungus) |
Usually in children Sometimes present in several family members | Microscopic examination of transparent tape that was applied to the anal area to check for pinworm eggs | |
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 | A doctor’s examination Examination of skin scrapings | |
Skin disorders | ||
An itchy, red, oozing, and crusty rash | A doctor’s examination | |
Cancer of the skin around the anus (perianal skin) | Scaly or crusty area | Examination of a tissue sample (biopsy) |
Sometimes itchy or painful patches on the skin | A doctor's examination | |
Small flap of tissue on the anus | A doctor’s examination | |
Medications | ||
Antibiotics | Current or recent use of an antibiotic | Elimination of the antibiotic to see whether symptoms are relieved |
Foods and dietary supplements | ||
Symptoms that occur after a substance is ingested | Elimination of the substance from the diet to see whether symptoms are relieved | |
Hygiene-related problems | ||
Excessive sweating described by the person, particularly with wearing of tight and/or synthetic clothing | Measures to limit sweating (such as wearing loose cotton underwear and changing underwear frequently) to see whether symptoms are relieved | |
Overly meticulous or aggressive cleansing of the anal area Poor cleansing | Extreme cleansing practices described by the person | A change in cleansing practices to see whether symptoms are relieved |
Skin irritants | ||
Anesthetic preparations, ointments, soaps, and sanitary wipes | Use of a possibly irritating substance described by the person | Avoidance of the substance to see whether symptoms are relieved |
* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. | ||
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, which most often occur in school-age children, are suspected, eggs can be collected from the anal region using sticky transparent tape to confirm the diagnosis (see diagnosis of pinworm infection).
Doctors may also examine the anus with a short, rigid tube (a procedure called anoscopy) to check for internal hemorrhoids.
Treatment of Anal Itching
Treatment of cause
Hygiene and symptom relief
The best way to treat anal itching is to treat the underlying disorder. For example, medications can be taken for parasitic infections (such as pinworms), and creams can be applied for fungal infections (such as Candida, also called yeast).
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.
Hygiene and symptom relief
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 helps combat excess moisture.
Clothing should be loose, and bed clothing should be lightweight.
Key Points
Pinworms in children and hygiene-related issues in adults are common causes of anal itching.
Foods and detergents or soaps can cause anal itching.
Appropriate hygiene practices (careful but gentle cleansing, avoiding strong soaps and chemicals, and decreasing skin moisture) can help relieve symptoms of anal itching.
