What are pinworms?

Q: My 4-year-old daughter attends a daycare where one child was diagnosed with having “pinworm.” Is this contagious. If so, what should I do about getting my child checked and treated? How does a child get pinworms, and what can I do to prevent this from happening to my child?
A: Pinworms are a common intestinal infection in preschoolers and school-age children. In fact, many children carry the worms for a while without ever getting diagnosed or treated. Although it’s not serious, it is contagious and can spread to other children and adults. So it’s good for you to know about pinworms, how they’re spread, and what symptoms to look for in your child and what to do to prevent the spread.

Pinworms are tiny, white, threadlike worms, about ½-inch long. The worm crawls out of the anus at night and lays microscopic eggs around the opening. The main symptom is itching and scratching around the anal area, or vulva in girls, especially at night. Pinworms are spread when the microscopic eggs around the child’s bottom get into the mouth of another person. This can happen when the child scratches his bottom and then touches other people directly or objects (such as toys, faucet handles and doorknobs) which other people touch; or by sharing towels, underclothes and bedding. Children also commonly reinfect themselves by touching their bottom then putting their hands in their mouths.

If you notice your daughter scratching her bottom, call her doctor. You can check for pinworms by waiting until she has been asleep for two to three hours, then taking a flashlight and spreading apart her buttocks to look around the anus for a worm. You can also press clear adhesive tape around the anus in the morning and the doctor can send it to the lab to be checked for the microscopic eggs.

If your daughter has pinworms, the doctor will prescribe an oral antiparasitic medicine, usually taken in just one or two doses. To help prevent your daughter from getting reinfected or infecting others:

  • Check everyone at home for pinworms and get treatment if needed.
  • Wash clothes, towels and bedding. Consider separate towels for family members.
  • Clean and disinfect frequently handled objects such as toys, faucet handles and doorknobs.
  • Keep your daughter’s fingernails short and discourage her from scratching her bottom and biting her nails.
  • Make sure everyone in the family washes their hands with soap and water after toileting and before handling food.
Karen Sokal-Gutierrez M.D., M.P.H. Pediatrician