Home > Health Library > Pinworms
Pinworms are a type of
parasite that lives in the
digestive system of humans. They are common throughout the world.
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.
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:
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.
Many people with pinworms don't have symptoms and don't know that they're infected. When symptoms occur, the most common ones are:
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.
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.
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 breastfeeding. So to reduce their risk of infection, a doctor may recommend that all other household members be treated with medicine.
Call your doctor if:
Pinworms spread easily and often come back. To reduce your chances of spreading the infection or getting infected again:
If anyone in your household gets pinworms again, the whole family may need to take medicine.
Learning about pinworms:
Other Works Consulted
American Academy of Pediatrics (2015). Pinworm infection. In DW Kimberlin et al., eds., Red Book: 2015 Report of the Committee on Infectious Diseases, 30th ed., pp. 621–622. Elk Grove Village, IL: America 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.
ByHealthwise StaffPrimary Medical ReviewerJohn Pope, MD - PediatricsSpecialist Medical ReviewerSusan C. Kim, MD - Pediatrics
Current as ofNovember 20, 2015
Current as of:
November 20, 2015
John Pope, MD - Pediatrics & Susan C. Kim, MD - Pediatrics
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