Pinworms

This is a common problem. It usually occurs when a child gets the worms' eggs under his nails and then puts his fingers into his nose or mouth. The eggs are swallowed and then the worms hatch and live in the appendix area of the large bowel. At night, the female worm lays her eggs just outside the rectum. This causes itching. The fingernails pick up new eggs, and the cycle of re-infection continues. A search at night with a flashlight may reveal a small, white, thinly coiled worm about 1/4 to 3/4 inch long around the anus and or vulva.

The life cycle of a pinworm is about 2-3 months. If your child has recurrence of symptoms after that time, it is because of a new infection, not because the initial infection was inadequately treated.
A family is not "unclean" if pinworms are discovered. They can be found in the best of homes. They are seldom serious and are mostly a nuisance, mainly causing itching of the "bottom". Occasionally, however, they can cause mild to moderate stomach cramps. If the infection occurs more than once in a home, the whole family may need to be treated

This is not an emergency. Do not call about pinworms after office hours but wait until the next business day for instructions.