Pruritus ani is the irritation of the skin at the exit of the

rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...

, known as the

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, d ...

, causing the desire to scratch. The intensity of anal

itch Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

ing increases from moisture, pressure, and rubbing caused by clothing and sitting. At worst, anal itching causes intolerable discomfort that often is accompanied by burning and soreness. It is estimated that up to 5% of the population of the United States experiences this type of discomfort daily.

Causes

If a specific cause for pruritus ani is found it is classified as "secondary pruritus ani". If a specific cause is ''not'' found it is classified as "idiopathic pruritus ani". The irritation can be caused by intestinal parasites, anal

perspiration Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distrib ...

, frequent liquid stools,

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...

, residual stool deposits, or the escape of small amounts of stool as a result of

incontinence Incontinence or Incontinent may refer to: *Fecal incontinence, the involuntary excretion of bowel contents *Urinary incontinence, the involuntary excretion of urine * Lack of moderation or self-control, especially related to sexual desire - see I ...

flatulence Flatulence, in humans, is the expulsion of gas from the intestines via the anus, commonly referred to as farting. "Flatus" is the medical word for gas generated in the stomach or bowels. A proportion of intestinal gas may be swallowed environm ...

. Another cause is

yeast infection Candidiasis is a fungal infection due to any type of '' Candida'' (a type of yeast). When it affects the mouth, in some countries it is commonly called thrush. Signs and symptoms include white patches on the tongue or other areas of the mouth ...

candidiasis Candidiasis is a fungal infection due to any type of '' Candida'' (a type of yeast). When it affects the mouth, in some countries it is commonly called thrush. Signs and symptoms include white patches on the tongue or other areas of the mouth ...

. Some diseases increase the possibility of yeast infections, such as

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...

infection. Treatment with

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

s can bring about a disturbance of the natural balance of intestinal flora, and lead to perianal thrush, a

affecting the anus.

Psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by raised areas of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small, localized patches to complete ...

also can be present in the anal area and cause irritation. Abnormal passageways (

fistula A fistula (plural: fistulas or fistulae ; from Latin ''fistula'', "tube, pipe") in anatomy is an abnormal connection between two hollow spaces (technically, two epithelialized surfaces), such as blood vessels, intestines, or other hollow or ...

s) from the small intestine or colon to the skin surrounding the anus can form as a result of disease (such as

Crohn's disease Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea (which may be bloody if inflammation is severe), fever, abdominal distension ...

), acting as channels which may allow leakage of irritating fluids to the anal area. Other problems that can contribute to anal itching include

pinworms Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic disease caused by the pinworm. The most common symptom is itching in the anal area. The period of time from swallowing eggs to the appearanc ...

hemorrhoid Hemorrhoids (or haemorrhoids), also known as piles, are vascular structures in the anal canal. In their normal state, they are cushions that help with stool control. They become a disease when swollen or inflamed; the unqualified term ''hemo ...

s, tears of the anal skin near the mucocutaneous junction (

fissures A fissure is a long, narrow crack opening along the surface of Earth. The term is derived from the Latin word , which means 'cleft' or 'crack'. Fissures emerge in Earth's crust, on ice sheets and glaciers, and on volcanoes. Ground fissure ...

), and

skin tag A skin tag, or acrochordon (pl. acrochorda), is a small benign tumor that forms primarily in areas where the skin forms creases (or rubs together), such as the neck, armpit and groin. They may also occur on the face, usually on the eyelids. ...

s (abnormal local growth of anal skin). Aside from diseases relative to the condition, a common view suggests that the initial cause of the itch may have passed, and that the illness is in fact prolonged by what is known as an

itch-scratch-itch cycle Lichen simplex chronicus (LSC) is lichenification, thick leathery skin with exaggerated skin markings caused by sudden pruritus, itching and excessive rubbing and Scratch reflex, scratching. It generally results in papule, small bumps, patches, ex ...

. It states that scratching the itch encourages the release of inflammatory chemicals, which worsen redness, intensifies itchiness and increases the area covered by dry skin, thereby causing a

snowball effect A snowball effect is a process that starts from an initial state of small significance and builds upon itself, becoming larger (graver, more serious), and also perhaps potentially dangerous or disastrous (a vicious circle), though it might be b ...

. Some authorities describe “psychogenic pruritus” or "functional itch disorder", where psychological factors may contribute to awareness of itching. Ingestion of

pinworm Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic disease caused by the pinworm. The most common symptom is itching in the anal area. The period of time from swallowing eggs to the appearance o ...

eggs leads to

enterobiasis Pinworm infection (threadworm infection in the UK), also known as enterobiasis, is a human parasitic disease caused by the pinworm. The most common symptom is itching in the anal area. The period of time from swallowing eggs to the appearance ...

, indicative of severe itching around the anus from migration of gravid females from the bowel. Severe cases of enterobiasis result in

hemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

and

eczema Dermatitis is inflammation of the Human skin, skin, typically characterized by itchiness, erythema, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become lichenification, thick ...

Diagnosis

Diagnosis is usually done with a careful examination of the anus and the patient's history. If the presentation or physical findings are atypical, biopsies can be done. In case of long-lasting symptoms, above all in patients over 50 years of age, a colonoscopy is useful to rule out a colonic polyp or tumor, that can show pruritus ani as first symptom.

Treatment

The goal of treatment is asymptomatic, intact, dry, clean perianal skin with reversal of morphological changes. For pruritus ani of unknown cause (idiopathic pruritus ani) treatment typically begins with measures to reduce irritation and trauma to the perianal area.

Stool softener Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...

s can help prevent constipation. If this is not effective topical

steroids A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and a ...

or injected

methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. Methylene blue is a thiazine dye. As a medication, it is mainly used to treat methemoglobinemia by converting the ferric iron in hemoglobin ...

may be tried. Another treatment option that has been met with success in small-scale trials is the application of a very mild (.006) topical capsaicin cream. This strength cream is not typically commercially available and therefore must be diluted by a pharmacist or end-user. If the itchiness is secondary to another condition such as infection or psoriasis these are typically treated. A successful treatment option for chronic idiopathic pruritus ani has been documented using a clean, dry and apply (if necessary) method. The person is instructed to follow this procedure every time the urge to scratch occurs. The treatment makes the assumption that there is an unidentified bacteria in the feces that causes irritation and itching when the feces makes contact with the anal and perianal skin during defecation, flatulation or anal leakage (particularly during sleep). Cleaning the area with warm water, avoiding all soaps and even baby wipes, then drying the area, ideally with a hair dryer to avoid irritation or failing that simply patting gently with a clean, dry, towel. If persons with pruritus ani do not need to scratch after these steps they are instructed to do nothing else. If the urge to scratch is still present they are instructed to apply a topical steroid cream which has antibiotic and antifungal properties. This will address a skin condition which may have become infected. Apply such a cream as directed by your medical professional but usually twice a day for one to two weeks. After this, they must maintain their clean and dry regime and apply an emollient ointment (not cream) to moisturize the skin. This should be applied after each bowel movement and at night. Continue until no longer needed. At any time, persons may use antihistamine treatments orally, to control the itching.

References

External links

* {{Diseases of the skin and subcutaneous tissue Pruritic skin conditions

Causes

Diagnosis

Treatment

See also

References

External links