Symptoms of threadworms 

Threadworms often go unnoticed by people who have them.

However, they can cause intense itching around the anus (and the vagina in girls), particularly at night when the female worms are laying eggs. This can disturb sleep.

In some cases, you may spot threadworms on your bed clothes or sheets at night, or you may notice them in your stools. The worms look like threads of white cotton and are about one centimetre long.

Severe or persistent threadworm infections can cause:

  • loss of appetite
  • weight loss
  • skin infection around the anus if bacteria enter any scratches caused by itching  wearing cotton gloves while sleeping may help prevent this
  • difficulty getting to sleep or staying asleep (insomnia)
  • bedwetting

In very rare cases, threadworms can spread outside the intestine to the urinary tract or liver, or the vagina or womb in girls or women.

Seeking medical help

Speak to your pharmacist about treatment if you suspect you or your child may have threadworms.

See your GP if:

  • you think you have threadworms and you're pregnant or breastfeeding
  • your child has threadworms and they're under two years old

Read more about treating a threadworm infection.

Page last reviewed: 24/08/2015

Next review due: 01/08/2018