Threadworms in Children: Signs, Treatment and Hygiene

Threadworms are tiny white worms that live in the gut. They are very common in children and are not dangerous. The main sign is an itchy bottom, worse at night. Treatment is a worm medicine for everyone at home, plus strict hand-washing. In Spain, one medicine is sold without a prescription and another needs one.

Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).

For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.

What are threadworms and how do children get them?

Threadworms are small roundworms that live in the bowel. The CDC says they are about the size of a staple. At night, female worms come out of the bottom to lay eggs on the skin nearby. That is what causes the itch.

When a child scratches, eggs get under the nails and onto the fingers. From there they reach the mouth, toys, clothes, bedding and food. Another person swallows them, and the cycle starts again. The NHS says eggs can survive up to 2 weeks.

They are most common in school-age and preschool children and the people who live with them.

What are the symptoms of threadworms in children?

Many children have no symptoms. When there are some, the NHS lists:

• Itching around the bottom, mainly at night.
• In girls, itching or soreness around the vagina.
• Waking at night and being irritable.
• Less often: wetting the bed again, or red, sore skin from scratching.

Scratching can break the skin and let germs in. Heavy infections are rare but can reduce appetite and weight, says MedlinePlus.

How do you check a child for threadworms?

Look for white, thread-like worms around the bottom or in the poo. The best time is an hour or two after your child falls asleep, or first thing in the morning.

A doctor may suggest the tape test. You press clear sticky tape around the bottom in the morning, before washing or using the toilet. The tape is checked for eggs under a microscope. It may be repeated on several mornings, as one test can miss the eggs.

How are threadworms treated in Spain, the UK and the US?

Treatment is a worm medicine by mouth. The difference between countries is which one you can buy without a prescription:

• Spain: pyrantel, sold as Trilombrin, is sold in pharmacies without a prescription (sin receta). Mebendazole, sold as Lomper, is listed on the AEMPS database as needing one.
• UK: mebendazole is sold in pharmacies without a prescription, usually as a chewable tablet or liquid.
• US: pyrantel pamoate is sold over the counter. Mebendazole and albendazole need a prescription.

Medicine kills the worms, not the eggs. So a doctor or pharmacist may advise a second treatment later. Follow the leaflet or their advice on when.

Treat everyone in the home at the same time, even if they have no symptoms. Both the NHS and the Trilombrin leaflet advise this. Petroleum jelly (vaselina) around the bottom can ease the itch.

Who should see a doctor before taking worm medicine?

• Children under 2. The NHS says to speak to a GP. The Spanish Trilombrin leaflet says it should be used under 2 only if a doctor decides the benefit outweighs the risk.
• Pregnant or breastfeeding women. The NHS advises asking a GP first. The Trilombrin leaflet does not recommend it in pregnancy unless a doctor thinks it essential.
• People with liver disease, or hereditary fructose intolerance (the liquid contains sorbitol).

If medicine is not suitable, the NHS says hygiene alone can clear threadworms. It must be kept up for 6 weeks.

What hygiene steps stop threadworms coming back?

The NHS advises these for 2 weeks after medicine, or 6 weeks without it:

• Wash hands often, always after the toilet and before eating.
• Keep nails short. Try to stop nail-biting and thumb-sucking.
• Shower or bathe every morning to wash off eggs laid in the night.
• Wear underwear or close-fitting pyjamas at night, and change them daily.
• Wash bedding, towels and sleepwear on a hot wash. Do not shake them first.
• Clean the toilet, bathroom surfaces and toys. Do not share towels.

Can my child go to school with threadworms?

Yes. The NHS says there is no need to stay off nursery, school or work. Tell the school if several children seem affected.

When should you see a doctor?

Threadworms are not an emergency. See a doctor if:

• Your child is under 2, or you are pregnant or breastfeeding.
• The itch is still there after treatment and careful hygiene.
• The skin is very red, hot, weeping or has pus.
• A girl has vaginal discharge, pain on peeing or bleeding.
• Your child loses weight or stops eating well.

Threadworms are a very common cause of an itchy bottom or vulva in young children. On their own they are not a sign of abuse. If you see injuries, bleeding or discharge you cannot explain, or your child says something that worries you, see a doctor. The doctor will also make sure the child is safe.

Call 112 if your child has severe belly pain, is floppy or very hard to wake. These are not threadworm signs and need urgent care.

Talking it through with a doctor by video

Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:

• Ask about the symptoms, who at home is affected and your child's age.
• Check whether the itch could be something else, such as eczema or a skin infection.
• Explain which treatment suits each member of the family, including pregnancy.
• Go through the hygiene plan and tell you when a face-to-face check is needed.

He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.

A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.

This guide is general information. It does not replace a consultation with your doctor.

Frequently asked questions

Sources

• NHS: Threadworms
• CDC: About pinworm infection
• MedlinePlus: Pinworms
• MSD Manual: Pinworm infection
• AEMPS CIMA: Trilombrin patient leaflet (in Spanish)

Related guides

• Online doctor visits for children in Spain
• Which medicines need a prescription in Spain
• Duty pharmacies in Spain
• Impetigo: symptoms and treatment
• Scabies and itchy skin infections