Anal itch, also known as pruritus ani, is an irritating, itchy sensation around the anus (the opening through which stool passes out of the body). Anal itch is a symptom, not an illness, and it can have many different causes. In most cases, a person with anal itch does not have a disease of the anus or rectum. Instead, the itchy sensation is a sign that one or more of the following has irritated the skin in the area:
Stool on the skin around the anal opening — If the anal area isn't cleaned properly after a bowel movement, a small amount of stool may be left behind on the skin, causing the area to itch. Less often, watery stools may leak out of the anal opening and cause itching. This sometimes happens in otherwise healthy people whose diets include very large amounts of liquids.
A diet containing foods or beverages that irritate the anus — A number of foods and drinks can irritate the anus, including spices and spicy foods, coffee (both caffeinated and decaffeinated), tea, cola, milk, alcoholic beverages (especially beer and wine), chocolate, citrus fruits, vitamin C tablets and tomatoes. Once a person eats or drinks something that can irritate the anus, it usually takes 24 to 36 hours before anal itching begins. That's the time it takes the food to travel through the digestive tract.
Treatment with antibiotics — Some powerful antibiotics that work against many different bacterial species can trigger anal itch by disturbing the normal ecology of the intestines. These drugs are called broad-spectrum antibiotics, and include tetracyclines and erythromycin (both sold under several brand names).
A local chemical irritation or skin allergy in the anal area — In sensitive people, chemicals and medications that are applied to the anal area can cause local irritation or allergic reactions. Some major culprits include dyes and perfumes used in toilet paper (especially scented toilet paper), feminine hygiene sprays and other deodorants for the area around the anus or genitals, medicated talcum powders, and medicated skin cleansers and soaps, especially perfumed soaps. Anal itch also can be triggered by over-the-counter medications (suppositories, creams, ointments) intended to treat anal problems.
Intense cleaning after a bowel movement — Although the anal area should be cleaned after every bowel movement, this cleaning must be gentle. Aggressive rubbing and scrubbing, especially with soaps or other skin cleansers, can irritate the skin and trigger anal itch.
Less often, anal itch is a symptom of some illness or condition that either affects the anal area alone, or involves larger areas of the digestive tract or skin. Some examples include:
Local diseases and conditions involving lower portions of the digestive tract — These include hemorrhoids, skin tags, rectal fistulas, rectal fissures and, rarely, anorectal cancer.
Infections and parasites — These include pinworms (especially in children), scabies, pediculosis, condyloma acuminata and skin infections due to Candida or tinea fungi.
Skin problems — These include psoriasis, eczema and seborrhea. In many cases, these conditions cause symptoms in several different areas of the skin surface, not only around the anus.
Worldwide, anal itch is a very common problem that occurs in up to 45 percent of people at some time during their lives. Men are affected two to four times more often than women. People who are overweight, perspire heavily or routinely wear tight-fitting underwear or hosiery are more likely to get anal itch.