Threadworms are tiny worms that infect the digestive tract. They're common in children and spread easily. They commonly cause an itch around the bottom and genitals.


Key points about threadworms

  • threadworms are common in young tamariki
  • threadworms can cause itching around the bottom and genitals 
  • if your child has worms - treat the whole family
  • see your family doctor if your child has ongoing symptoms of worms 
  • read below for ways to prevent threadworms from spreading or coming back 

What are threadworms?

Worms are common in preschool and school-aged tamariki. The most common type of worm is a threadworm, also called a pinworm. Worms are a type of parasite that infects the digestive tract. 

What are the signs and symptoms of worms in children? 

Threadworms cause tamariki to get a very itchy bottom, usually worse at night. In girls, itching and redness can also be around the vulva and vagina. Tamariki may complain of a ‘shooting pain’ in the vagina. 

Other symptoms tamariki may experience include:

  • not sleeping well
  • not wanting to eat as much
  • being irritable 

For some children, worms can cause vulvovaginitis. This is where the outer female genitals get inflamed and irritated.

See the KidsHealth page on vulvovaginitis to learn more

What causes worms?

Worms spread from person to person. Threadworms live in the lower digestive tract but come out of the bottom at night to lay their eggs. They can also lay their eggs around the vagina. This causes the bottom and genitals to feel very itchy. 

Threadworms are spread when tamariki scratch their bottom, collecting eggs under their fingernails. These eggs can then be carried back to the mouth or spread in food or on other items. Threadworm eggs can survive for 2 weeks outside the body. 

What should I do if I think my child has worms? 

You can talk to your local pharmacist about over-the-counter treatment options. Follow the instructions on the packet and from the pharmacist. Having a shower the night they take their medicine and again the next morning can help wash away the eggs laid during the night.

Your whole family will need treatment at the same time, even if they don’t have symptoms. If your child is under 2 years old, see your family doctor. 

Can worms come back?

Repeat threadworm infections are common in tamariki. Two or three treatments may be needed when threadworms lay their eggs in and around the vagina.

Alongside the medicine, there are other ways to help prevent threadworms from returning.

Hygiene measures

Encourage your child not to scratch their genital area. Keep your child's fingernails trimmed and clean, and try to stop them from biting their nails or sucking their fingers. Remind your child to wash their hands thoroughly after using the toilet.

House cleaning

Hotwash your child's bedding, towels and pyjamas. Regularly clean surfaces in the house your child touches often, like door handles. Vacuum the floor regularly to remove eggs.

When should I take my child to see the doctor? 

If your child continues to have an itch around their bottom or genitals despite threadworm treatment, take them to the doctor. Sometimes, they may need treatment more than once. The doctor may want to test your child's poo. 

You should also take your child to the doctor if they pass a large worm or have tummy pain, nausea or vomiting.

This page last reviewed 31 August 2023.

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