Pinworms are small, white, thin, straight, pin-sized worms which inhabit the rectum and the colon. They emerge during sleep onto the perianal skin causing intense itching. There are no adverse effects from pinworms other than possible mild vaginitis or vaginal inflammation caused by itching in girls.
Pinworms can be acquired by acquiring eggs from the skin during scratching and transferring them to the mouth. They may also be swallowed when inhaled while handling clothes and bedclothes of infected individuals. If your child exhibits marked anal itching, it is not unreasonable to check for pinworms.
Pinworms are easily treated with oral antiparasitic medicines including Pin-X, which is available over the counter. It is often necessary to treat each member of the family, although pregnant women should not take this medication. While pinworms can be quite annoying, they are certainly not life threatening and not an emergency situation.