Enterobiasis overview

# Overview
Enterobiasis is an infection commonly caused by Enterobius vermicularis (pinworm). It usually affects children and causes perianal pruritus, restlessness, and irritability. The diagnosis is made by physical examination and repeated scotch-tape tests. This infection is medically treated with two doses of either pyrantel pamoate, albendazole, or mebendazole. The transmission of enterobiasis can be prevented by treating all the household members of the infected person and improving personal and household hygienic conditions (e.g., frequent hand washing, changing clothes, and covering food).

# Historical Perspective
Enterobius vermicularis eggs found in western Utah are carbon dated to 7837 BC. In 1983, Jean-Pierre Hugot isolated a new species Enterobius gregorii which is identical to Enterobius vermicularis.

# Classification
There is no established classification system for enterobiasis, though it may be classified on the basis of the organisms causing it; Enterobius vermicularis and Enterobius gregorii.

# Pathophysiology
Enterobius vermicularis is usually transmitted via the feco-oral route to the human host. It reproduces in the small intestine of humans only. The gravid female worm lays eggs in the perianal area usually at night and causes pruritus. In addition to the fingernail contamination, the infective eggs can be transmitted via the dust and fomites.

# Causes
Enterobiasis is caused by pinworm. The pinworm (genus Enterobius), also known as threadworm (in the United Kingdom and Australia) or seatworm, is a parasitic worm.  It is a nematode (roundworm) and a common intestinal parasite or helminth, especially in humans. The medical condition associated with pinworm infestation is known as enterobiasis (a type of helminthiasis) or less precisely as oxyuriasis in reference to the family Oxyuridae.

# Differentiating (Disease name) from other Conditions
Enterobiasis must be differentiated from other causes of perianal pruritus and the nematode infections.

# Epidemiology and Demographics
Enterobiasis is particularly common in children. Annually, around 200 million people are infected worldwide. The pinworm is the most common helminth (i.e., parasitic worm) infection in the United States and Western Europe.

# Risk Factors
Common risk factors in the development of enterobiasis are young age, unhygienic practices, and close contact with infected person.

# Screening
There is insufficient evidence to recommend routine screening for enterobiasis.

# Natural History, Complications and Prognosis
If left untreated, patients with enterobiasis may progress to develop secondary skin infections. Common complications of enterobiasis include bacterial dermatitis, folliculitis, vulvovaginitis, and recurrent cystitis. Prognosis is generally excellent.

# Diagnosis

## History and Symptoms
The symptoms of enterobiasis may include painful itching around the anus, restless sleep, poor appetite, and failure to gain weight. When the infection is heavy, there can be a secondary bacterial infection due to the irritation and scratching of the anal area.

## Physical Examination
Patients with enterobiasis usually appear restless. Physical examination of patients with enterobiasis is remarkable for skin excoriations as a result of scratching (secondary to perianal itch), perianal skin infections, and visualization of adult worms in the perianal area (usually at night).

## Laboratory Findings
Diagnosis of enterobiasis is often made clinically by observing the female worm(s) in the peri-anal region, but can also be made using the "scotch-tape" test, in which the sticky side of a strip of cellophane tape is pressed against the peri-anal skin, then examined under a microscope for pinworm eggs.

## Chest X Ray
There are no X-ray findings associated with enterobiasis.

## Echocardiography or Ultrasound
There are no echocardiography or ultrasound findings associated with enterobiasis.

## Other Imaging Findings
There are no other imaging findings associated with enterobiasis.

# Treatment

## Medical Therapy
The treatment of enterobiasis involves the administration of such antiparasitic drugs as either mebendazole (Vermox), albendazole, piperazine (Antepar), or pyrantel pamoate (Combatrin, Povan). A repeat dose is recommended two weeks after the initial treatment. More than one household member is likely to be infected, so the entire household is often treated.

## Surgery
Surgical intervention is not recommended for the management of enterobiasis.

## Primary Prevention
Effective measures for the primary prevention of enterobiasis include treating family members, frequent handwashing, improving personal and household hygienic condition.

## Secondary Prevention
The primary and secondary prevention strategies for enterobiasis are the same.