Pruritus ani
Encyclopedia
Pruritus ani is the irritation of the skin at the exit of the rectum
, known as the anus
, causing the desire to scratch. The intensity of anal itch
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.
, residual stool deposits, or the escape of small amounts of stool as a result of incontinence
or flatulence
. Another cause is yeast infection or Candidiasis
. Some diseases increase the possibility of yeast infections, such as diabetes mellitus
or HIV
infection. Treatment with antibiotic
s can bring about a disturbance of the natural balance of intestinal flora, and lead to perianal thrush
, a yeast infection, affecting the anus. Psoriasis
also can be present in the anal area and cause irritation. Abnormal passageways (fistula
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
), acting as channels which may allow leakage of irritating fluids to the anal area. Other problems that can contribute to anal itching include pinworms, hemorrhoid
s, tears of the anal skin near the mucocutaneous junction, (fissures
), and skin tags (abnormal local growth of anal skin).
Anal itching is conjectured to be possibly caused by irritating chemicals in foods consumed, but no clinical evidence based on scientific enquiry has been asserted to demonstrate this.
Some authorities describe “psychogenic pruritus” or "functional itch disorder" http://www.medicaljournals.se/acta/content/download.php?doi=10.2340/00015555-0266, where psychological factors may contribute to awareness of itching.
, or injected methylene blue
may be tried. If the itchiness is secondary to another condition such as infection or psoriasis these are typically treated.
Rectum
The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. The human rectum is about 12 cm long...
, known as the anus
Anus
The anus 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, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
, causing the desire to scratch. The intensity of anal itch
Itch
Itch is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response...
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.
Causes
The irritation can be caused by intestinal parasites, anal perspiration, frequent liquid stools, diarrheaDiarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, residual stool deposits, or the escape of small amounts of stool as a result of incontinence
Fecal incontinence
Fecal incontinence is the loss of regular control of the bowels. Involuntary excretion and leaking are common occurrences for those affected. Subjects relating to defecation are often socially unacceptable, thus those affected may be beset by feelings of shame and humiliation...
or flatulence
Flatulence
Flatulence is the expulsion through the rectum of a mixture of gases that are byproducts of the digestion process of mammals and other animals. The medical term for the mixture of gases is flatus, informally known as a fart, or simply gas...
. Another cause is yeast infection or Candidiasis
Candidiasis
Thrush redirects here. For the hoof infection see Thrush .Candidiasis or thrush is a fungal infection of any of the Candida species , of which Candida albicans is the most common...
. Some diseases increase the possibility of yeast infections, such as diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
or HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
infection. Treatment with antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s can bring about a disturbance of the natural balance of intestinal flora, and lead to perianal thrush
Thrush
-Birds:* Thrush , any of the many birds in the Turdidae family* Antthrush, any of a group of birds within the Formicariidae family* Dohrn's Thrush-babbler , a species of bird in the Timalidae family...
, a yeast infection, affecting the anus. Psoriasis
Psoriasis
Psoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of...
also can be present in the anal area and cause irritation. Abnormal passageways (fistula
Fistula
In medicine, a fistula is an abnormal connection or passageway between two epithelium-lined organs or vessels that normally do not connect. It is generally a disease condition, but a fistula may be surgically created for therapeutic reasons.-Locations:Fistulas can develop in various parts of the...
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
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
), acting as channels which may allow leakage of irritating fluids to the anal area. Other problems that can contribute to anal itching include pinworms, hemorrhoid
Hemorrhoid
Hemorrhoids or haemorrhoids , are vascular structures in the anal canal which help with stool control. They become pathological or piles when swollen or inflamed. In their physiological state they act as a cushion composed of arterio-venous channels and connective tissue that aid the passage of...
s, tears of the anal skin near the mucocutaneous junction, (fissures
Anal fissure
An anal fissure is a break or tear in the skin of the anal canal. Anal fissures may be noticed by bright red anal bleeding on the toilet paper, sometimes in the toilet. If acute they may cause severe periodic pain after defecation but with chronic fissures pain intensity is often less...
), and skin tags (abnormal local growth of anal skin).
Anal itching is conjectured to be possibly caused by irritating chemicals in foods consumed, but no clinical evidence based on scientific enquiry has been asserted to demonstrate this.
Some authorities describe “psychogenic pruritus” or "functional itch disorder" http://www.medicaljournals.se/acta/content/download.php?doi=10.2340/00015555-0266, where psychological factors may contribute to awareness of itching.
Treatment
For pruritus ani of unknown cause treatment typically begins with measures to reduce irritation and trauma to the peri anal area. Stool softeners can help prevent constipation. If this is not effective topical steroids, capsaicinCapsaicin
Capsaicin 2CHCH=CH4CONHCH2C6H3-4--3- ) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact...
, or injected methylene blue
Methylene blue
Methylene blue is a heterocyclic aromatic chemical compound with the molecular formula C16H18N3SCl. It has many uses in a range of different fields, such as biology and chemistry. At room temperature it appears as a solid, odorless, dark green powder, that yields a blue solution when dissolved in...
may be tried. If the itchiness is secondary to another condition such as infection or psoriasis these are typically treated.
See also
- Pruritus scrotiPruritus scrotiPruritus scroti is itchiness of the scrotum that may be secondary to an infectious cause.-References:...
- Pruritus vulvaePruritus vulvaePruritus vulvae is pruritus of the vulva, which is the counterpart of pruritus scroti, and may be caused by many different causes.- Causes :This condition is a symptom of an underlying condition more often than it is a primary condition....
- Perianal candidiasisPerianal candidiasisPerianal candidiasis is a skin condition caused by infection by Candida albicans, and may present as pruritus ani....
- Pruritus
- List of cutaneous conditions