A pinworm (Enterobius vermicularis) is a small, pale yellow or white worm of about one centimeter long. It belongs to the roundworms and is an intestinal parasite. Pinworms live in the lower part of the colon and in the caecum. They are fairly common in schoolchildren. Infection with pinworms is harmless but nasty.


People may become infected with pinworms by swallowing eggs of this parasite. The eggs end up in the intestines, where they develop into larvae. From the larvae, adult worms emerge in the colon and they reside there. The adult worms reproduce and the female worms come out at night and lay eggs in the skin around the anus. Infected people (mostly children) go scratching and the eggs stick to the fingers and under the nails. The eggs can then stick to anything: food, toys, sandbox, doorknobs and to other people. These eggs can remain alive outside the body for a long time. The infection can also be contracted by inhaling dust containing the eggs of the parasite.
The worms live for about eight weeks. The time between taking eggs and secrete them again is four to six weeks.


Pinworms can cause nasty symptoms. Characteristic is the overnight intense itch in the anus, in the gluteal cleft and sometimes in the labia. In addition, (vague) abdominal pain and nausea may occur. The itch can keep some people from sleep. Scratching can cause inflammation and a broken skin.


The diagnosis of pinworm is based on the symptoms and physical examination. The stool is examined under the microscope in order to identify the eggs of the pinworm and to confirm the diagnosis. The eggs can also be collected by applying transparent adhesive tape at the skin around the anus in the morning and examine the adhesive tape on a slide. The worms are sometimes visible with bare eyes at the skin around the anus or in the nightwear.


Infection with pinworms is treated by anti-worm agents (anthelmintics). Family members of the infected person should also be treated this way.


By starting appropriate treatment and paying attention to hygiene, a person can get rid of the worms quickly.


Ensure good hygiene to prevent infection and reinfection of family members: