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There are many different types of intestinal worms, but the most common is threadworm (also called pinworm). Threadworm is a type of roundworm that is commonly found in preschool and school-aged children, however the whole family can become infected.
Threadworm causes a very itchy bottom, which is usually worse at night. If your child is infected with threadworm, it is not usually serious and can be treated easily with medication.
If your child has threadworm, they may:
In girls, there may also be redness and itching around the vaginal area. (Threadworms may cause or worsen vulvovaginitis in girls. See our fact sheet
You may be able to see threadworm if you examine your child at night. Take a torch, separate your child’s buttocks and look carefully around the anus (and the opening to the vagina in girls). You might see tiny white threads that may be moving.
Threadworm gets its name because the worms look like white threads, which are about 1 cm long. The worms live in the lower intestine, but they come out of the anus over night to lay their eggs in the area between the buttocks, which causes your child’s bottom to feel very itchy. It is estimated that one female threadworm can lay up to 16,000 eggs.
Threadworm is spread when children scratch their bottom, causing the eggs to collect under the fingernails. The child then carries the worm eggs back to their mouth with their hands. The eggs can also be spread indirectly, in food, dust, or other items. The eggs can survive up to two weeks outside the body.
Once your child swallows threadworm eggs, the eggs hatch in your child’s small intestine and the worms travel down to their anus.
You cannot catch threadworm from animals.
You can talk to a pharmacist about over-the-counter treatment options. Drugs such as pyrantel (Combantrin) or mebendazole (Banworm) are very safe and often recommended. Follow the instructions on the packet, bearing in mind special precautions may be given for children under two years of age and for pregnant women.
Unfortunately, repeat threadworm infection is very common. To help reduce this and to prevent the threadworms from spreading to others, you can take the following precautions:
If you have tried a threadworm treatment for your child and their symptoms have not improved, take them to your GP. The doctor will examine your child and may want to do blood or faeces (poo) tests. Also take your child to the GP if:
Do I need to to worm my children and my pets at the same time?
No. Humans cannot catch threadworm from animals.
Is ringworm and threadworm the same thing?
No, ringworm is not actually a worm at all. It is a fungus that needs to be treated with anti-fungal medication.
Developed by The Royal Children's Hospital General Medicine and Infectious Diseases departments. We acknowledge the input of RCH consumers and carers.
Reviewed September 2020.
Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au.
This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.