What is pinworm infection?
This infection is caused by a small, white
intestinal worm called Enterobius vermicularis (EN-ter-O-be-us ver-MIK-u-lar-is).
Pinworms are about the length of a staple and live in the rectum of humans.
While an infected person sleeps, female pinworms leave the intestines through
the anus and deposit eggs on the surrounding skin.
What are the symptoms of a pinworm infection?
Itching around the anus,
disturbed sleep, and irritability are common symptoms. If the infection is
heavy, symptoms may also include loss of appetite, restlessness, and difficulty
sleeping. Symptoms are caused by the female pinworm laying her eggs. Most
symptoms of pinworm infection are mild; many infected people have no symptoms.
Who is at risk for pinworm infection?
Pinworm is the most common worm
infection in the United States. School-age children, followed by preschoolers,
have the highest rates of infection. In some groups nearly 50% of children are
infected. Infection often occurs in more than one family member. Adults are less
likely to have pinworm infection, except mothers of infected children. Child
care centers, and other institutional settings often have cases of pinworm
How is pinworm infection spread?
Pinworm eggs are infective within a few
hours after being deposited on the skin. They can survive up to 2 weeks on
clothing, bedding, or other objects. You or your children can become infected
after accidentally ingesting (swallowing) infective pinworm eggs from
contaminated surfaces or fingers.
Pinworm Infection Symptoms
What are the symptoms of pinworms?
Intense itching around the anus and/or vagina are the classic symptoms of pinworms. Less common pinworm infection symptoms range from
- upset stomach to loss of appetite,
- irritability, restlessness, and
Most infected individuals have few or no symptoms but, if the infection is heavy, the symptoms can be correspondingly more severe.
How is pinworm infection diagnosed?
If pinworms are suspected, transparent
adhesive tape (often called the "scotch tape test") or a pinworm paddle
(supplied by your health care provider) are applied to the anal region. The eggs
become glued to the sticky tape or paddle and are identified by examination
under a microscope. Because bathing or having a bowel movement may remove eggs,
the test should be done as soon as you wake up in the morning. You may have to
provide several samples to your health care provider for examination. Since
scratching of the anal area is common, samples taken from under the fingernails
may also contain eggs. Eggs are rarely found during lab examinations of stool or
urine. At night, the adult worms can sometimes be seen directly in bedclothes or
around the anal area.
How is pinworm infection treated?
With either prescription or
over-the-counter drugs. You should consult your health care provider before
treating a suspected case of pinworm. Treatment involves a two-dose course. The
second dose should be given 2 weeks after the first.
What if the pinworm infection occurs again?
The infected person should be
treated with the same two-dose treatment. Close family contacts should also be
treated. If the infection occurs again, you should search for the source of the
infection. Playmates, schoolmates, close contacts outside the house, and
household members should be considered. Each infected person should receive the
usual two-dose treatment. In some cases it may be necessary to treat with more
than two doses. One option is four to six treatments spaced 2 weeks apart.
How can I prevent the spread of infection and reinfection?
- Bathe when you
wake up to help reduce the egg contamination.
- Change and wash your underwear
each day. Frequent changing of night clothes are recommended.
- Change underwear,
night clothes, and sheets after each treatment. Because the eggs are sensitive
to sunlight, open blinds or curtains in bedrooms during the day.
hygiene should include washing hands after going to the toilet, before eating
and after changing diapers.
- Discourage nail-biting and
scratching bare anal areas. These practices help reduce the risk of continuous
Cleaning and vacuuming the entire house or washing sheets
every day are probably not necessary or effective. Screening for pinworm
infection in schools or institutions is rarely recommended. Children may return
to day care after the first treatment dose, after bathing, and after trimming
and scrubbing nails.
SOURCE: Centers for Disease Control and Prevention
Childhood Diseases: Measles, Mumps, & More
Last Editorial Review: 5/22/2007