NHS Factsheet

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Threadworms

Read about threadworms (pinworms), which are tiny worms in your poo. They're common in children and spread easily. You can treat them without seeing a GP.

30 August 2022

Introduction

Threadworms (pinworms) are tiny worms in your poo. They're common in children and spread easily. You can treat them without seeing a GP.

Check if it's threadworms

You can spot worms in your poo. They look like pieces of white thread.

You might also see them around your child's bottom (anus). The worms usually come out at night while your child is sleeping.

  • extreme itching around the anus or vagina, particularly at night
  • irritability and waking up during the night

Less common signs of worms include:

  • weight loss
  • wetting the bed
  • irritated skin around the anus

A pharmacist can help with threadworms

You can buy medicine (mebendazole) ↗ for threadworms from pharmacies. This is usually a chewable tablet or liquid you swallow.

Treat everyone in your household, even if they do not have symptoms.

Tell the pharmacist if you need to treat a child under 2, or if you're pregnant or breastfeeding. Treatment might not be suitable and you may need to speak to a GP.

Find a pharmacy ↗

Things you should do at home

Medicine kills the threadworms, but it does not kill the eggs. Eggs can live for up to 2 weeks outside the body.

There are things you can do to stop becoming infected again.

Do

  • wash hands and scrub under fingernails – particularly before eating, after using the toilet or changing nappies

  • encourage children to wash hands regularly

  • bathe or shower every morning

  • rinse toothbrushes before using them

  • keep fingernails short

  • wash sleepwear, sheets, towels and soft toys (at a hot temperature)

  • disinfect kitchen and bathroom surfaces

  • vacuum and dust with a damp cloth

  • make sure children wear underwear at night – change it in the morning

Don't

  • do not shake clothing or bedding, to prevent eggs landing on other surfaces

  • do not share towels or flannels

  • do not bite nails or suck thumbs and fingers

Nursery, school and work

If you or your child has threadworms there's no need to stay off nursery, school or work.

How threadworms spread

Threadworms spread when their eggs are swallowed. They lay eggs around your bottom (anus), which make it itchy. The eggs get stuck on your fingers when you scratch. They can then pass on to anything you touch, including:

  • clothes
  • toys
  • toothbrushes
  • kitchen or bathroom surfaces
  • bedding
  • food
  • pets

Eggs can pass to other people when they touch these surfaces and then touch their mouth. They take around 2 weeks to hatch.

Children can get threadworms again after they've been treated for them if they get the eggs in their mouth. This is why it's important to encourage children to wash their hands regularly.