HealthInfo Aoraki South Canterbury

Threadworms

Noketui

Threadworms (also known as pinworms, or just worms) are a common small white worm that can live in your gut (bowel). At night, the female worm crawls out to lay eggs in the skin around your bottom (anus).

Anyone can be infected by threadworms, but they are most common in tamariki (children) of school age.

Threadworms are spread by swallowing the eggs. This happens if you scratch, causing the eggs to get under your fingernails. They can then get onto your clothes, bedding, toys or furniture. You can infect yourself by putting your hand in your mouth. Other people can get the eggs on their hands from things you have touched.

Threadworms only live in people, so you cannot get them from pets or other animals. They are mostly spread between whānau (family) members.

Symptoms of threadworms

Often there are no symptoms. But threadworms can cause intense itching around the bottom, where the worms lay their eggs. This especially happens at night. You might notice your tamaiti (child) scratching their bottom a lot, or they might tell you it is itchy. You might see white threads in their poo or around their bottom.

Treating threadworms

You can treat worms with a medicine called mebendazole. You can get this on prescription from your general practice team or directly from your pharmacist. It is sensible to treat the whole household to prevent threadworms spreading or coming back. You should take the treatment again after 2 weeks to prevent reinfection, as the eggs of threadworms can last outside the body.

Good hygiene is as important as the medicine to get rid of eggs and stop you getting infected again. Wash all your sleepwear, bedding and towels. Vacuum carpets and wipe down surfaces in your house, especially your bathroom.

Getting help with threadworms

You should see your general practice team if the symptoms continue after treatment with mebendazole.

Also check with your doctor if you are pregnant, or have children aged under 2.

Reducing the spread of threadworms

To reduce the risk of spreading threadworms, practise good hand hygiene. This is especially important after going to the toilet, and before handling and eating food.

Wash underwear, bedclothes and bed linen regularly.

  HealthInfo recommends the following pages

• KidsHealth – Threadworms in children

  More detailed information about threadworms.

Written by HealthInfo clinical advisers. Last reviewed May 2025.

Sources

Page reference: 49701

Review key: HITHR-49701