Anal Itching (Pruritus Ani/ Hemorrhoids) Causes, Prevention and Treatment.

Anal itching or hemorrhoid is a swollen vein in the anal canal. Figuratively, hemorrhoids may be best described as clumps of tissue located in the anal canal that contain blood vessels (hemorrhoidal cushions). 

Anal itching facts

• Anal itching is itching around the anus.
• Examples of causes of anal itching include hemorrhoids, anal fissures, pinworms, foods, medications, and other diseases or conditions.
• Additional symptoms associated with anal itching include burning and pain if the anal skin is traumatized by scratching.
• The diagnosis of the cause of anal itching requires examination of the anus for common anal problems such as hemorrhoids or fissures, skin diseases such as psoriasis or cancer, infectious diseases such as pinworms or yeast, and leakage of stool.
• Treatment of anal itching depends on the cause.

What is anal itching?

Anal itching is the irritation of the skin at the exit of the rectum, known as the anus, accompanied by the desire to scratch. Although itching may be a reaction to chemicals in the stool, it often implies that there is inflammation of the anal area. The intensity of anal itching and the amount of inflammation increases from the direct trauma of scratching and the presence of moisture. At its most intense, anal itching causes intolerable discomfort that often is described as burning and soreness.

What causes anal itching?

• Anal itching can be caused by irritating chemicals in the foods we eat, such as are found in spices, hot sauces, and peppers.
• Anal itching also can be caused by the irritation of continuous moisture in the anus caused by frequent liquid stools, diarrhea, or escape of small amounts of stool (incontinence). Moisture increases the possibility of infections of the anus, especially yeast, particularly in patients with diabetes or HIV.
• Treatment with antibiotics also can lead to a yeast infection and irritation of the anus.
• Psoriasis also can irritate the anus.
• Abnormal passageways (fistulas) from the small intestine or colon to the skin surrounding the anus can form as a result of disease (such as Crohn's disease), and these fistulas bring irritating fluids to the anal area.

Other problems that can cause anal itching include:

• pinworms,
• hemorrhoids,
• tears of the anal skin (fissures), and
• skin tags (abnormal local growth of anal skin).

What are additional symptoms associated with anal itching?

• The intensity of anal itching and the amount of inflammation increases from the direct trauma of scratching and the presence of moisture.
• At its most intense, anal itching causes intolerable discomfort that often is described as burning and soreness, especially during and after bowel movements.
• There also may be small amounts of bleeding.

What is the treatment for anal itching?

Initial treatment of simple itching is directed toward relieving the burning and soreness. It is important to clean and dry the anus thoroughly and avoid leaving soap in the anal area.

• Cleaning efforts should include gentle showering without direct rubbing or irritation of the skin with either the washcloth or towel.
• After bowel movements, moist pads (such as baby wipes, flushable moist wipes, and flushable anal cleansing wipes) should be used for cleaning the anus instead of toilet paper.
• If there is constant moisture present in the anus or stool incontinence, it may be necessary to clean the anus with moist pads between bowel movements.

Many over-the-counter (OTC) products are sold for the treatment of anal itching and are available as ointments, creams, gels, suppositories, foams and pads. These products often contain the same drugs used to treat hemorrhoids.

• When used around the anus, ointments, creams, and gels should be applied as a thin covering.
• When applied to the anal canal, these products should be inserted with a finger using finger cots (latex covers for the fingertips) or a "pile pipe." Pile pipes are most efficient when they have holes on the sides as well as at the end. Pile pipes should be lubricated with ointment prior to insertion.
• Suppositories or foams do not have advantages over ointments, creams, and gels.

Most products contain more than one type of active ingredient. Almost all contain a protectant in addition to another ingredient. Only examples of brand-name products containing one ingredient in addition to the protectant are discussed in this article.

Local anesthetics

Local anesthetics temporarily relieve pain, burning, and itching by numbing the nerve endings. The use of these products should be limited to the perianal area and lower anal canal. Local anesthetics can cause allergic reactions with burning and itching. Therefore, the application of anesthetics should be discontinued if burning and itching increase.
Examples of local anesthetics include:

• benzocaine 5% to 20% (Americaine Hemorrhoidal, Lanacane Maximum Strength, Medicone)
• benzyl alcohol (Itch-X) 5% to 20%
• dibucaine 0.25% to 1.0% (Nupercainal)
• dyclonine 0.5% to 1.0%
• lidocaine (Xylocaine) 2% to 5%
• pramoxine 1.0% (Fleet Pain-Relief, Procto Foam Non-steroid, Tronothane Hydrochloride)
• tetracaine 0.5% to 5.0%

Vasoconstrictors

Vasoconstrictors are chemicals such as epinephrine, a naturally occurring chemical. Applied to the anus, vasoconstrictors make the blood vessels become smaller, which may reduce swelling. They also may reduce pain and itching due to their mild anesthetic effect.
Vasoconstrictors applied to the perianal area - unlike vasoconstrictors given by injection - have a low likelihood of causing serious side effects, such as high blood pressure, nervousness, tremor, sleeplessness, and aggravation of diabetes or hyperthyroidism.
Examples of vasoconstrictors include:

• ephedrine sulfate 0.1% to 1.25%
• epinephrine 0.005% to 0.01%
• phenylephrine 0.25% (Medicone Suppository, Preparation H, Rectocaine)

Protectants

Protectants prevent irritation of the perianal area by forming a physical barrier on the skin that prevents contact of the irritated skin with aggravating liquid or stool from the rectum. This barrier reduces irritation, itching, pain, and burning. There are many products that are themselves protectants or that contain a protectant in addition to other medications.
Examples of protectants include:

• aluminum hydroxide gel
• cocoa butter
• glycerin
• kaolin
• lanolin
• mineral oil (Balneol)
• white petrolatum
• starch
• zinc oxide (Desitin) or calamine (which contains zinc oxide) in concentrations of up to 25%
• cod liver oil or shark liver oil if the amount of vitamin A is 10,000 USP units/day.

Astringents

Astringents cause coagulation (clumping) of proteins in the cells of the perianal skin or the lining of the anal canal. This action promotes dryness of the skin, which in turn helps relieve burning, itching, and pain.
Examples of astringents include:

• calamine 5% to 25%
• zinc oxide 5% to 25% (Calmol 4, Nupercainal, Tronolane)
• witch hazel 10% to 50% (Fleet Medicated, Tucks, Witch Hazel Hemorrhoidal Pads)

Antiseptics

Antiseptics inhibit the growth of bacteria and other organisms. However, it is unclear whether antiseptics are any more effective than soap and water.
Examples of antiseptics include:

• boric acid
• phenol
• benzalkonium chloride
• cetylpyridinium chloride
• benzethonium chloride
• resorcinol

Keratolytics

Keratolytics are chemicals that cause the outer layers of skin or other tissues to disintegrate. The rationale for their use is that the disintegration allows medications that are applied to the anus and perianal area to penetrate into the deeper tissues.
The two approved keratolytics used are:

• aluminum chlorhydroxy allantoinate (alcloxa) 0.2% to 2.0%
• resorcinol 1% to 3%

Analgesics

Analgesic products, like anesthetic products, relieve pain, itching, and burning by depressing receptors on pain nerves.
Examples of analgesics include:

• menthol 0.1% to 1.0% (greater than 1.0% is not recommended)
• camphor 0.1% to 3% (greater than 3% is not recommended)
• juniper tar 1% to 5%

Corticosteroids

Corticosteroids reduce inflammation and can relieve itching, but their chronic use can cause permanent damage to the skin. They should not be used for more than short periods of a few days to two weeks. Only products with weak corticosteroid effects are available over-the-counter. Stronger corticosteroid products that are available by prescription should not be used for treating anal itching.

What if anal itching persists?

For persistent anal itching, efforts are directed toward identifying an underlying cause. An examination by a doctor can rapidly identify most causes of anal itching. Adjustments in diet, treatment of infections, or surgical procedures to correct the underlying cause may be required. 

SOURCE: UpToDate. Approach to the patient with anal pruritus.