Adult pinworms are about
0.5 in. (12.7 mm) long and look like little white threads. Pinworm eggs are so tiny, you'd
need a microscope to see them.
What causes pinworm infection?
Most people get infected by accidentally swallowing pinworm
eggs. Anyone can get pinworms, but they are most common in school-aged children. They are usually spread like this:
A child swallows pinworm eggs, and they travel to the child's intestines. In about a month, the eggs hatch into worms. At night the female worms crawl out the rectum and lay eggs around the child's anus.
When the worms lay eggs, it can cause itching. If the child scratches, the eggs can cling to the child's fingers and get stuck under the fingernails.
The eggs then stick to things the child touches, such as clothing, dishes, toys, and furniture. The eggs can live 2 to 3 weeks outside the body.
When you touch something the child has touched, the eggs get on your hands. Then if you touch food or your mouth, you can swallow the eggs. This starts the cycle over again.
spread easily in homes, day care centers, schools, and other places
where groups of people spend time together. So if one person in your family has pinworms, others
probably do too.
It's possible to get pinworms by inhaling airborne eggs, but this is rare. It's also rare to get pinworms from a swimming pool.
Pinworms are spread from person to person. Pets don't get pinworms and can't spread them to humans.
What are the symptoms?
Many people with pinworms don't have symptoms and don't know that they're infected. When symptoms occur, the most common ones are:
Itching around the anus.
Restless sleep, because itching is often worse at night.
Pinworms can be annoying. But they don't carry disease, and they rarely cause
serious health problems. Sometimes people
get a skin infection from scratching.
How are pinworms diagnosed?
To find out if you have pinworms, your doctor will ask about your past health and check the skin around your
The doctor may ask you to do a transparent tape test at home. To do the test, you press a piece of clear, sticky tape on the skin around your anus in the morning before you get up. The doctor will put the tape under a microscope
to look for pinworm eggs. You might need to repeat this test a few times.
How are they treated?
You can treat pinworms with
over-the-counter or prescription medicine that kills the worms. Treatment can help keep you from getting infected again and from spreading
the infection to other people.
You will probably need two doses, 2 weeks apart. That's because the medicine kills the worms but not the eggs. The second dose will kill any worms that hatch after the first treatment.
Pinworm medicine may not be safe for children younger than 2 and women who are pregnant or breast-feeding. So to reduce their risk of infection, a doctor may recommend that all other household members be treated with medicine.
Call your doctor if:
Medicine hasn't cleared up the infection.
is causing side effects.
You have new or worse symptoms.
How can you keep from spreading pinworms or getting them again?
Pinworms spread easily and often come back. To reduce your chances of spreading the infection or getting infected again:
Wash your hands carefully and often. Teach your children to do the same, especially after they use the toilet and before they handle food.
fingernails short, and don't scratch the itch. Wearing gloves at night may help prevent scratching.
Bathe or shower every day.
Don't share or reuse towels or washcloths.
Change your underwear and bedding each morning.
Wash clothes, bedding, and towels regularly. Dry them in a hot dryer.
If anyone in your household gets pinworms again, the whole family may need to take medicine.
The American Academy of Pediatrics (AAP) offers a
variety of educational materials about parenting,
general growth and development, immunizations, safety, disease prevention, and more. AAP guidelines for various conditions and links to other
organizations are also available.
Centers for Disease Control and Prevention (CDC):
1600 Clifton Road
Atlanta, GA 30333
U.S. Centers for Disease Control and Prevention (CDC)'s website on parasites offers information on diseases caused by parasites. It provides information on topics such as malaria, neglected tropical diseases, and parasitic infections in the United States. There are also links to related information, such as a glossary and a site on healthy water, and other references and resources, such as statistics on parasitic diseases.
KidsHealth for Parents, Children, and
Nemours Home Office
10140 Centurion Parkway
Jacksonville, FL 32256
This website is sponsored by the Nemours Foundation. It
has a wide range of information about children's health—from allergies and
diseases to normal growth and development (birth to adolescence). This website
offers separate areas for kids, teens, and parents, each providing
age-appropriate information that the child or parent can understand. You can
sign up to get weekly emails about your area of interest.
National Institute of Allergy and Infectious Diseases
(NIAID), National Institutes of Health
NIAID Office of Communications and Government Relations
6610 Rockledge Drive, MSC 6612
Bethesda, MD 20892-6612
The National Institute of Allergy and Infectious
Diseases conducts research and provides consumer information on infectious and
American Academy of Pediatrics (2009). Pinworm infection (Enterobius vermicularis). In LK Pickering et al., eds., Red Book: 2009 Report of the Committee on Infectious Diseases, 28th ed., pp. 519–520. Elk Grove Village, IL: American Academy of Pediatrics.
Drugs for parasitic infections (2010). Treatment Guidelines From The Medical Letter, 8(Suppl): e1–e20.
Hotez PJ (2009). Parasitic nematode infections. In RD Feigin et al., eds., Feigin and Cherry's Textbook of Pediatric Infectious Diseases, 6th ed., vol. 2, pp. 2981–2996. Philadelphia: Saunders Elsevier.
Van Voorhis WC (2010). Helminthic infections. In EG Nabel, ed., ACP Medicine, section 7, chap. 35. Hamilton, ON: BC Decker.
How this information was developed to help you make better health decisions.