Threadworms in children (ages one to five)

What are threadworms?

Threadworms (pinworms) are tiny worms that can live in your child's intestines (Knott 2018, NHS 2017). They're very small, between 2mm and 13mm long, and look like pieces of fine white cotton thread (Knott 2018, NICE 2018).

If your child catches threadworms, they can be an itchy nuisance, but they're likely to be completely harmless (NICE 2018). Fortunately, they're easy to treat with medicine, and you can help to keep them at bay by following a simple hygiene routine (NICE 2018).

Threadworms are most common in preschoolers and older children, but babies and adults can catch them too (NHS 2015, NICE 2011b). It's thought that about two in five children will get them at some point (NICE 2018).

What causes threadworms in children?

Children usually catch threadworms by touching something that has threadworm eggs on it, then putting their fingers in their mouth (NICE 2018).

Threadworms lay their eggs around the bottoms of people who've been infected (NICE 2018). This makes the area very itchy, tempting children to scratch (NICE 2018). When they do scratch, it's easy for them to get eggs on their fingers, and these eggs can then end up on surfaces such as toys, bedding or clothing (NICE 2018).

Threadworm eggs aren't visible to the naked eye, and they can live on surfaces for up to two weeks (NICE 2018). They can also end up as part of the general dust in your home as they fall or are shaken off objects (Knott 2018, NICE 2018). When this happens, it's also possible for your child to catch them by breathing them in (NICE 2018).

It's easy for threadworms to pass from person to person, and there's no surefire way to prevent them. Your child can easily catch them while at nursery, or out and about, so having worms doesn't necessarily mean there are any problems with his hygiene. It's a common condition that can happen to anyone.

It's thought that pets can’t catch or carry threadworms, so your child won’t catch threadworms from an animal (NICE 2018). Your child may get threadworms from touching a pet, though, if someone with the infection has transferred eggs onto the animal’s fur by stroking it (NHS 2018).

However the eggs enter your child’s body, once they’re there, they travel to her intestines where they hatch, releasing threadworms. Threadworms can live in the gut for up to six weeks, during which time they can lay thousands of eggs (NICE 2018). This is one reason why the condition is so common in young children.

What are the symptoms of threadworms?

Some people don’t get any symptoms at all when they catch threadworms (NICE 2018). But usually, if your child has threadworms, she will have a very itchy bottom (NHS 2018). Girls can also get itchiness around the vagina (NICE 2018).

This itchiness may be worse at night, because this is usually when the threadworms come out of the bottom to lay their eggs (NICE 2018). Your child may have trouble sleeping because of the itchiness, and feel generally irritable. (NHS 2018, NICE 2018)

If your child scratches a lot, the skin around her bottom may become irritated and sore (NHS 2018). Your child isn't likely to have any other symptoms, but some children do experience:

• stomach ache
• loss of appetite
• bed wetting, if she's usually dry at night
  (NHS 2018)

The most surefire way to tell if your child has threadworms is to look for them. You may be able to spot them in your child’s poo (NICE 2018). They look like tiny white threads, less than 1.5cm long (NICE 2018).

Another way to check is to have a look at your child’s bottom late in the evening, after she’s gone to sleep (NICE 2018). You may be able to spot the threadworms as they come out to lay their eggs (NICE 2018)

To check for threadworms at night, gently part your child's buttocks and shine a torch around the opening of her bottom (Knott 2018). If she has threadworms, although they’re tiny, you may be able to see one or two crawling out, or around her pyjamas and bed sheets (Knott 2018).

If you're not sure whether your child has threadworms, see your GP. She might ask you to do the tape test, to find out for certain (Knott 2018). This involves putting a small piece of sticky tape on your child's bottom, first thing in the morning – before wiping or bathing. This is when eggs are most likely to appear. You'll then be asked to put the tape in a special container and send it to a lab, where experts will check to see if there are any eggs on the tape (Knott 2018). This test isn't always necessary though.

How are threadworms treated?

Threadworms are easy to get rid of. However, it can take a little while longer to completely rid your home of the eggs, and prevent threadworms coming back (NICE 2018, NHS 2018).

If your child's over two years old, ask your pharmacist about a medicine called mebendazole, which will safely kill the threadworms in her gut (NICE 2018). It's available as a liquid for children, and chewable tablets for adults (NHS 2018). Because threadworms are very contagious, and not everyone who gets them has symptoms, you should treat everyone in your family at the same time to guard against re-infection (NICE 2018).

The medicine for threadworms isn't always suitable for children under two, or women who are pregnant or breastfeeding (NICE 2018). If anyone in your home falls into these groups, see your GP to make sure they get the right treatment (NICE 2018).

Although mebendazole will kill the threadworms, it won't kill any eggs (NHS 2018). If your child – or anyone else in your home - swallows new eggs, they may get threadworms again (NHS 2018).

So it's important to clean the whole house to get rid of the threadworm eggs, and continue to clean frequently for two weeks (NICE 2018). This is how long the eggs can survive on surfaces and objects around your home (NICE 2018).

If anyone in your home isn't able to take mebendazole (for example, if they're pregnant, breastfeeding or too young), you'll need to follow the below hygiene steps for six weeks (NICE 2018). This is because anyone not taking mebendazole could still have threadworms, which could continue to lay new eggs. After six weeks, any threadworms in the gut will have died naturally, so there won't be any new eggs (NICE 2018).

The following hygiene tips will help to rid your home of threadworm eggs:

• Wash your hands regularly, and encourage your child to do the same. Be particularly careful before eating, and after using the toilet or changing nappies.
• Encourage your child to avoid biting her nails or sucking her fingers. Where possible, also encourage her to avoid scratching her bottom. However, threadworms can be very itchy, so don't be surprised if this is easier said than done! You could try using anti-scratch mittens, or dressing her in a onesie at night so she can't touch her bottom.
• Keep fingernails short where possible, and scrub underneath them when washing hands.
• Take a bath or shower every morning, to wash off new eggs that threadworms might have laid in the night.
• If your child is still in nappies, change her nappy first thing in the morning. If she's potty-trained, make sure she wears underwear at night, and change it for fresh underwear in the morning.
• Regularly wash bedding, sleepwear, towels and soft toys. A normal temperature wash should be enough to kill the eggs.
• Avoid shaking clothing or bedding, which can cause eggs to fly off onto other surfaces.
• Vacuum your home regularly to remove any eggs that may have got into your household dust.
• Wipe down surfaces with a damp cloth, to avoid sweeping eggs into the air.
• Disinfect surfaces in the kitchen and bathroom.
  (NHS 2018)

Following these tips may feel like a pain, especially when you're on your third laundry load of the day. But the more closely you follow them, the sooner your home will be free of threadworm eggs, and the lower the risk of your child getting threadworms again.

If your child still has symptoms two weeks after taking mebendazole (or after six weeks of following the hygiene precautions if she can't take mebendazole), go back to your GP (NICE 2018). He may recommend another dose of medicine and give you extra tips to keep your home egg-free (NICE 2018). If your child keeps getting symptoms, he may refer you to a pediatrician, who will make sure your child gets the best treatment (NICE 2018).

Do I need to keep my child away from nursery if she has threadworms?

Your child can still go to nursery or preschool if she has threadworms (NICE 2018). Just make sure you wash her bottom in the morning and change her nappy or knickers (NHS 2018). Put her in clean clothes and wash her hands and fingernails (NHS 2018). This will help to make sure she doesn’t have any threadworm eggs on her when she goes to nursery.

Learn the difference between threadworms and ringworm.