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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 (see Table: Causes and Features of Anal Itching), such as pinworms or a fungal infection. Of the specific causes, only inflammatory bowel disease and anal cancer (rare causes) 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 (see 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.
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
Causes and Features of Anal Itching
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).
Pinworms are rarely the cause of anal itching. However, 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 Pinworm Infection).
Doctors may also examine the anus 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.
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