Threadworms, also known as pinworms, are tiny parasitic worms that hatch eggs in and infect the large intestine of humans.
Threadworms are the most common type of worm infection in the UK, and they are particularly common in young children under the age of 10.
Threadworms are white and look like small pieces of thread. You may notice them around your child's bottom or in your or your child's stools.
They don't always cause symptoms, but people often notice itchiness around their bottom or vagina. This can be worse at night and can sometimes disturb sleep
Do I need to avoid work or school?
A threadworm infection should be treated as soon as it's identified, but it is not necessary to stay off work or school.
However, it's important to inform your child's school or nursery so they can follow good hygiene practices to limit the spread of infection – such as cleaning toys and equipment, and encouraging children to wash their hands regularly
Who is at risk?
Threadworm infections are most common in young children because they often forget to wash their hands after going to the toilet and they often share things like toys with other children.
People who are in close contact with someone who has a threadworm infection, for instance living in the same house, are also at a high risk of infection. This is why all members of a household where someone has a threadworm infection need to be treated.
Threadworms often go unnoticed by people who have them, but symptoms can include:
intense itching around the anus (or the vagina in girls), particularly at night when the female worms are laying eggs
disturbed sleep as a result of the itching, which can lead to irritability
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 about one centimetre long.
Severe or persistent threadworm infections can cause:
loss of appetite
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)
Causes and Spread
A female threadworm can lay thousands of tiny eggs around the anus or vagina. While laying eggs, the female threadworm also releases a mucus that causes itching.
Scratching the anus or vagina, or wiping them after going to the toilet, can result in the eggs becoming stuck on your fingertips or under your fingernails.
If you don't wash your hands, the eggs can then be transferred to your mouth or onto food or objects – such as toys and kitchen utensils. If someone else eats the contaminated food or touches the contaminated object and then touches their mouth, they will become infected.
After the eggs have been swallowed they will pass into a person's intestine, where they will hatch. After about two weeks the threadworms will have grown into adults, at which point they will reproduce and the cycle of infection will start again.
Threadworm eggs can be transferred from your anus (or vagina) to anything that you touch, including:
bed sheets and bed clothes
flannels and towels
kitchen or bathroom surfaces
Threadworm eggs can survive on surfaces for up to three weeks. They can be swallowed after touching contaminated surfaces
To successfully treat threadworms, all household members must be treated, even if they have no symptoms.
This is because the risk of the infection spreading to other people in the same household is very high.
The aims of treatment are to get rid of the threadworms and prevent re-infection. This will usually involve a combination of medication to kill the worms and strict hygiene measures to stop the spread of the eggs.
The main medication used to treat threadworms is available from your local pharmacy without prescription, but make sure you follow the manufacturer’s instructions because it is not suitable for everyone.
Mebendazole is the main medication used to treat threadworm infections. It can be bought over the counter from your local pharmacy or prescribed by your GP and is available as a chewable tablet or as a liquid. Strict hygiene measures can help clear up a threadworm infection and reduce the likelihood of re-infection.
The life span of threadworms is approximately six weeks, so it's important that the hygiene methods are followed for at least this long. Everyone in the household must follow the advice outlined below
Wash all night clothes, bed linen, towels and soft toys when you are first diagnosed. This can be done at normal temperatures but make sure that the washing is well rinsed.
Thoroughly vacuum and dust the whole house, paying particular attention to the bedrooms. This should be repeated regularly.
Carefully clean the bathroom and kitchen by damp-dusting surfaces and washing the cloth frequently in hot water. This should be repeated regularly.
Avoid shaking any material that may be contaminated with eggs, such as clothing or bed sheets. This will help prevent eggs being transferred to other surfaces.
Don't eat food in the bedroom, because you may end up swallowing eggs that have been shaken off the bedclothes.
Keep your fingernails short. Encourage other members of your household to do the same.
Discourage nail-biting and sucking fingers. In particular, make sure that children don't suck their thumb.
Wash your hands frequently and scrub under your fingernails, particularly before eating, after going to the toilet and before and after changing your baby's nappy.
Wear close-fitting underwear at night and change your underwear every morning.
Bath or shower regularly, particularly first thing in the morning. Make sure that you clean around your anus and vagina to remove any eggs.
Ensure that everyone in your household has their own face flannel and towel. Don't share towels.
Keep toothbrushes in a closed cupboard and rinse them thoroughly before use.
We hope this information is useful.