Anal Itching
(Pruritus Ani)
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. The intensity of anal itching increases from moisture, pressure, and abrasion caused by clothing and sitting. At its most intense, anal itching causes intolerable discomfort that often is described as burning and soreness.
Anal itching is medically referred to as pruritus ani.
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. It also can be caused by the irritation of frequent liquid stools, diarrhea, or escape of small amounts of stool (incontinence). Diseases that increase the possibility of yeast infections, such as diabetes mellitus or HIV infection, as well as treatment with antibiotics 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).
How is anal itching treated?
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 should be used for cleaning the anus instead of toilet paper.
Many over-the-counter products are sold for the treatment of anal itching.
These often contain the same drugs that are used for treating hemorrhoids.
Products used for the treatment of anal itching are available as ointments,
creams, gels, suppositories, foams, and pads. Ointments, creams, and gels--when
used around the anus--should be applied as a thin covering. When applied to the
anal canal, these products should be inserted with a finger 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 below.
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, if burning and itching
increase with the application of anesthetics, they should be discontinued. Local
anesthetics include:
- Benzocaine 5% to 20% (Americaine Hemorrhoidal,
Lanacane Maximum Strength, Medicone)
- Benzyl alcohol 5% to 20%
- Dibucaine 0.25% to 1.0% (Nupercainal)
- Dyclonine 0.5% to 1.0%
- Lidocaine 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 that resemble 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 that are taken orally or 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. Vasoconstrictors include:
- Ephedrine sulfate 0.1% to 1.25%
- Epinephrine 0.005% to 0.01%
- Phenylephrine 0.25% (Medicone Suppository, Preparation H, Rectacaine)
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.
Protectants include:
- Aluminum hydroxide gel
- Cocoa butter
- Glycerin
- Kaolin
- Lanolin
- Mineral oil (Balneol)
- White petrolatum
- Starch
- Zinc oxide 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.
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
- Hydrastis
- 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 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.
Next: What if anal itching persists? »
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