Definition Pinworms are a type of roundworm that commonly infests humans, especially children.
What is going on in the body? Pinworm infestation occurs all over the world. Humans are the only known hosts. A person gets pinworms by swallowing the eggs of the worm. Pinworm eggs remain alive for up to 3 weeks. They are passed on by person-to-person contact or by touching a contaminated item, such as a toy. The first symptoms may not appear for 1 to 2 months or longer.
Pinworms generally find a home in the colon, or large intestine. At night, they come through the anus to lay their eggs on the surrounding skin outside of it. Sometimes the worms migrate to other areas of the body, such as the tube that takes urine from the bladder outside the body, called the urethra, the vagina, the tubes connecting the ovaries with the uterus, called the fallopian tubes, or the pelvis, causing inflammation.
After leaving the bowel to lay eggs or migrate to other parts of the body, the worms usually die, so the infection can be self-limiting. Often, though, children, and sometimes adults, re-infect themselves.
What are the signs and symptoms of the infection? An itchy anus is the most common symptom of pinworms. It is caused by the adult worm migrating out through the anus to lay eggs. This usually occurs at night, which is when the itching will be most intense.
What are the causes and risks of the infection? The roundworm, Enterobius vermicularis, may be passed to others through direct contact or indirectly by handling a contaminated item.
What can be done to prevent the infection? Presently there is no way to prevent pinworms.
How is the infection diagnosed? Pinworms are diagnosed by finding the adult worms around the anus, usually 2 to 3 hours after a child or other person goes to sleep, or in faeces. One way to check for eggs is to briefly place and remove a piece of clear adhesive tape over the anus. The tape can then be examined for signs of pinworms directly or with a microscope.
What are the long-term effects of the infection?
What are the risks to others? A person who has pinworms may contaminate other people and items that he or she handles.
What are the treatments for the infection? Treatment is not usually needed, though parents are often concerned about the pinworms in their children. One dose of a combination of the drugs mebendazole and pyrantel pamoate is usually given and repeated again 2 weeks later. All family members need to take the medication to rid them of pinworms.
What are the side effects of the treatments? The side effects may include:
Author: Danielle Zerr, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
