Pinworm Disease

About This Disease

Pinworm disease is a relatively common infection of the intestines by a parasitic worm called Enterobius vermicularis. Pinworms are about the length of a staple. The disease occurs most frequently in preschool-age and school-age children, and in mothers of infected children.

Life Cycle

Signs and Symptoms

Infection with pinworms usually causes itching around the anus, and irritability, often because of disrupted sleep. Some individuals with pinworm infection may not have any symptoms. Symptoms are caused by the female pinworm laying her eggs on the skin. After ingesting a pinworm egg, it takes about 1 to 2 months or longer for an egg to grow to an adult who can lay eggs around the anus.

Transmission

You get the disease by ingesting (eating) pinworm eggs. The eggs travel to the intestines where they hatch and mature. The mature worms then travel to the anus, where they deposit a new batch of eggs, usually at night. Contamination of the hands, clothing, and bedding can take place at this time. Transmission occurs when the eggs are transferred to a person’s mouth, by hand from anus-to-mouth, or indirectly, by putting pinworm-contaminated items into the mouth.

 

Diagnosis

There is no laboratory tests available to diagnose pinworm infections. Stool samples are not recommended because pinworm eggs and worms are not common in stool. There are three techniques to diagnose pinworm infections. The first is to look for the worms near the anus 2 to 3 hours after the infected person is asleep. The second is to touch the anus with clear tape first thing in the morning to possibly collect eggs. The eggs will be visible on the tape under a microscope. The tape test should be done on three consecutive mornings. The third option is to look at samples from under the fingernails with a microscope. An infected person could have picked up eggs from scratching.

Treatment

Antiparasitic medications prescribed by a doctor are effective in pinworm infections. Household and intimate contacts may also require treatment. Reinfection is common and several treatments may be necessary if exposure to the parasite continues.

Immunity

There is no immunity to pinworm infections. You may be re-infected if you are exposed again. It is also possible to re-infect yourself.

Risk in Hawaii

There are no statistics on how many people have been infected with pinworms in Hawaii. In the United States, children under 18, people who take care of infected children, and people who are institutionalized are the most at risk to becoming infected with pinworms.

Prevention

  • Eliminate the source of infection by treating cases.
  • Wash the hands thoroughly before handling food or before eating.
  • Keep the fingernails short, discourage nail-biting, and avoid scratching the anal area.
  • Take early morning showers to help wash away any eggs deposited overnight around the anal area.
  • Change to clean underclothing, night clothes, and bed sheets daily, preferably after bathing. Take special care to avoid spreading eggs when changing bed sheets.
  • Vacuum the house, classroom, or workplace daily for several days after starting treatment of cases.

Additional Resources

Information for Clinicians