Pinworms are tiny worms that can live in the lower digestive tract of people. They are harmless but cause severe rectal itching, which is often the only symptom.

Pinworms can be picked up from dirt, grass, or playgrounds, or from family members or playmates. Young children are more likely to get pinworms because they aren't as careful as adults about washing their hands and what they put in their mouths. Pinworm eggs are so small they can't be seen and are easily spread. Often, all members of the family can get pinworms.


Once worm eggs are swallowed, they grow into adult worms in the intestines. The female worms then lay thousands of very tiny eggs around the anus of the infected person, usually at night. The presence of the worms on the skin around the anus causes severe rectal or sometimes vaginal itching.

This itching can cause nervousness and crankiness during the day, restlessness and trouble sleeping at night, and often causes the person to scratch and get new eggs on their hands and under their fingernails. Anything touched by someone with pinworms can get pinworm eggs on it.


When you call, the nurse will talk to you about what's happening with your child. An appointment might be made. Medicine is usually prescribed for pinworms. A test is sometimes done on a sample of stool or skin to see which medicine will be most helpful.

After medical center hours, contact the Consulting Nurse Service.

You might be asked to pick up a special slide at the lab or from the nurse and collect a sample from your child. When collecting a sample:

Because the medicine doesn't kill pinworm eggs, it is given in two doses two weeks apart. The first dose kills the pinworms. The second dose kills any pinworms that have hatched from eggs after the first dose was given. It is very important that both doses be given.

What you can do:

Clinical review by Emily Chao, DO
Group Health
Reviewed 02/15/2012