Maya Mundkur Greer, MSN,

The pinworm, or Enterobius vermicularis, is a parasite that commonly infects the intestines of humans. The male is 2 to 5 millimeters long and lives in the lower gastrointestinal tract. Females can be twice as long as males. Eggs take 1 to 2 months to mature in the gastrointestinal tract and become large enough to migrate. Pregnant females typically migrate to the rectal area to lay eggs, often during the night. Pinworms may also deposit their eggs along the perineum and even in the vagina. The females usually die after depositing their eggs.
Humans are the only known natural hosts; the living area or living in an institution; sharing pinworms do not live in dogs and cats.
beds; and living in a warm, moist climate.
Clinical Course
Pinworm infection can cause intense itchiness Pinworm infection can be spread in several in the perianal region. Persistent scratching can ways, most commonly by direct contact with the Pinworm Eggs. These eggs of the produce an excoriated rash. The discomfort from eggs. People can continually reinfect themselves human parasite pinworms usually results in restless sleep. Thank- by scratching the perianal area and touching their Enterobius fully, the infection is self-limited, and serious mouths or touching objects that are then eaten or vermicularis, or complications are rare.
placed in the mouth.
"human pinworm", Pinworms also spread through indirect contact have been captured on cellulose tape. when someone touches clothes, underwear, or Photo courtesy Pinworm infection occurs worldwide and is bedding that contain eggs. These eggs can then of the CDC very common. Prevalence rates are higher among spread to food, toys, or other objects that often go pre-school and school-aged children. Up to 50 into children's mouths. Eggs can also be dispersed percent of institutionalized persons may be infected. around a room when contaminated articles are While infection in adults is far less common, chil- shaken, causing the eggs to settle into dust. In dren with pinworms often infect parents and other ideal conditions, the eggs can live up to 3 weeks household members.
on bedding, clothing, and dust; however, less than Variables that increase risk of infection include: 1 out of 10 eggs will be alive after 2 days at room age (5–10 years old); presence of other children in temperature.
The Health Care of Homeless Persons - Part I - Pinworm 97 A third mode of transmission is "retro-infec- Mebendozole (Vermox™) is an antihelminthic tion". This happens when the pinworms reinfect that comes in chewable tablets of 100 mg and has the host by hatching in the perianal region and then few side effects. Available by prescription, this migrating back into the rectum.
medication is not recommended for pregnant women or children under two years of age. Albendazole (Albenza™) is a pinworm medica- Perianal and perineal itching, especially at tion available by prescription that is usually reserved night, and a rash coupled with insomnia are the for infections that are not cleared by the other most common complaints of pinworm infection. preparations. A single 400 mg tablet is given by However, many pinworm infections are entirely mouth. Once again, this medication is not recom-without symptoms.
mended for pregnant women or children under the The presence of pinworms can be confirmed age of two.
in one of two ways. The first is direct observation Treatment with a second dose of medication of the adult worms around the anus, perineum, or (Vermox™, Antiminth™, or Albenza™) 14 days entrance to the vagina. The optimum time to see the after the first dose has a cure rate of 90 percent. In worms is 1 to 2 hours after a child has gone to bed or rare circumstances 4 to 6 treatments may be neces-on awakening in the morning. A flashlight will help sary to get rid of the infection.
with the search. A second test is to observe the eggs, Vaseline™ and other over the counter creams which are about the size of the head of a pin, under or ointments can help relieve the itching caused by
a microscope. A 2-inch strip of scotch tape can be pinworms when applied to the perianal area.
applied to the child's perianal area in the morning
before the child awakens. The tape may then be Prevention and Control
transferred to a glass slide for examination.
The control of pinworms calls for personal and Pinworms can be identified about 50% of the environmental hygiene. Staff must be particularly time after a single attempt at one of these tests. sensitive to an individual's feelings of guilt or These tests should be repeated over 3 to 5 consecu- embarrassment. Pinworms can infect the cleanest tive mornings before accepting a negative result. household. When discussing hygiene, staff should Pinworm infection usually runs in families, and a emphasize the ease of transmission and frequency of diagnosis in one person calls for the examination of reinfection. Pinworms can spread easily to a whole all family and household members.
family and throughout an entire family shelter unless the source is treated.
During treatment for pinworms, the linens, Most people in single family households will get bedclothes, underwear, and toys of infected rid of pinworms without treatment. Unfortunately, individuals should be washed in hot (131°F/55°C) larger group settings such as shelters and day care soapy water. If washing is not possible, then the centers facilitate transmission and persistent infec- articles should be thoroughly vacuumed. Before tion. Breaking the cycle of reinfection through cleaning, you can avoid dispersing the eggs into the direct and indirect contact can be very difficult. air by handling every article with minimal shaking. Early treatment and thorough examination of Staff and guests should damp dust, damp mop, family members and close friends will increase the and/or vacuum the living space of infected guests chances of eradication. If children in different and common rooms daily for several days after families are diagnosed with pinworms within a treatment to reduce the number of eggs that may short time, the entire shelter or day care facility may reside in dust.
require treatment.
If the entire shelter needs treatment, all linens, Pyrantel pamoate (Antiminth™) kills pinworms bedclothes, and living space should be considered at dosages of 11 mg/kg to a maximum dose of 1 infected. Guests and staff should clean all articles gram. Antiminth™ can be used in people of all and spaces as described above.
ages and is not contraindicated in pregnant women. The following measures also help to reduce Some people develop headaches and stomach pains transmission:when taking the drug, but these side effects are • discourage scratching in the anal area; uncommon. Antiminth™ is currently available • the use of gloves and close fitting bed without a prescription. Brand names include "Pin- clothes can be helpful; X" and "Reese's Pinworm Medication".
• trim nails to minimize biting; 98 The Health Care of Homeless Persons - Part I - Pinworm The Health Care of Homeless Persons - Part I - Pinworm 99 • wash hands with warm, soapy water before child can then put his or her hands into the mouth preparing, serving, or eating food and after or onto objects such as toys or food. The eggs are using the toilet or changing diapers.
also easily spread around a room when infected • avoid shaking or fanning the bedding.
linen or clothing is shaken. When one person in a family is found to have pinworms, the entire family needs to be examined. Pinworms are tiny worms that live in a person's When the infected person and close contacts are intestines. Female pinworms crawl to the rectal area treated early, there is little risk to the rest of the at night to lay eggs, causing the infected person to shelter. If several cases happen in different families, itch and to sleep restlessly. While uncomfortable, the entire shelter may need treatment. pinworms rarely cause serious complications. Pinworms reappear easily, but careful hygiene However, they are easily spread among people who reduces the prospect of reinfection during treat-live or play closely together, particularly children. ment. You should consult the local board of When a child scratches, the eggs of pinworms can health and caregivers for specific control measures get on the hands and under the fingernails. The regarding this infection. E Pinworm Medication List
Brand Name
Antiminth (Pin-X, Reese's Pinworm References
Pinworm infection. In: Pickering LK, et al., eds. 2000 Red Book: Report of the Committee on Infectious Disease. Elk
Grove Village, IL: American Academy of Pediatrics; 2000:449-451.
Bundy DAP, et al. Nematodes limited to the intestinal tract (Enterobius vermicularis, Trichuris trichuira, and Capillaria phillippinensis). In: Strickland GT, ed. Hunter's Tropical Medicine and Emerging Infectious Diseases. Philadelphia: WB Saunders; 2000:719-726.
Drugs for parasitic infection. Medical Letter on Drugs and Therapeutics 1998;40(1017):1-12.
Enterobiasis (Pinworm disease). In: Benenson AS, ed. Control of Communicable Disease in Man. Washington D.C.: American Public Health Association; 1990:157-159.
Hearns VL. Pinworms. In: Rakel RE, ed. Saunders Manual of Medical Practice. Philadelphia: W.B. Saunders; 2000.
Nelson JD, Bradley JS. Nelson's Pocket Book of Pediatric Antimicrobial Treatment. Lippincott Williams and Wilkins; Pinworm infestation. In: Berkow R, ed. The Merck Manual. Rahway, New Jersey: Merck and Company; 2000: Owen RL. Parasitic diseases. In: Sleisenger MH, Fordtran JS, eds. Gastrointestinal Disease: Pathophysiology, Diagnosis, and Management. Philadelphia: W.B. Saunders Company; 1989.
Urbach AH. Pinworms. In: Burg FD, et al., eds. Gellis and Kagan's Current Pediatric Therapy. Philadelphia: WB Saunders Company; 1999.
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