Threadworms: How to Get Rid of Them With Pharmacy Treatment, and Stop Them Coming Back

Threadworms are the question parents most want to ask quietly. Every September and October, once children are back in classrooms sharing pencils and toys, I see the same thing: a parent hovering by the counter until it is empty, then leaning in to say their child has "something in their poo". If that is you, please do not be embarrassed. Threadworms are extremely common, they are not a sign of a dirty home, and in most cases we can sort them out at the counter in five minutes, without a GP appointment.

This guide covers what I actually tell families: who needs the tablet, who does not, why the treatment fails when it fails, and when a pharmacy is not the right place.

What are threadworms, and how do you know you have them?

Threadworms (also called pinworms) are tiny worms that live in the gut. The NHS threadworms page describes them as looking like pieces of white thread in poo. You might also see them around your child's bottom, usually at night, because that is when the female worms come out to lay their eggs.

The signs to look for:

• small white threads in poo, or around the bottom at night
• intense itching around the bottom (or the vagina in girls), worse at night
• irritability and broken sleep
• less commonly, bed-wetting, weight loss, or sore skin around the bottom from scratching

The itching is the clue most parents notice first. A child who is suddenly restless every night, scratching in their sleep, with no obvious reason, is worth checking with a torch shortly after they fall asleep.

How do you get rid of threadworms?

The treatment we use is a medicine called mebendazole, sold in pharmacies as Ovex. For threadworms it is a single dose: one chewable tablet, or one dose of the liquid. It works in the gut, so side effects are uncommon and usually mild (some tummy discomfort, wind or diarrhoea).

The rules I go through with every family:

• Treat everyone in the household aged 2 and over, on the same day, even people with no symptoms. Threadworms spread so easily that by the time one child is itching, someone else usually has them too.
• Take a second dose 2 weeks later if symptoms come back. The NHS advises that a repeat dose may be needed after 2 weeks if the itching or worms return.
• Crush the tablet for younger children, or use the liquid. The NHS mebendazole guidance says to always crush the tablet for children.
• No need to stay off school, nursery or work. The NHS is clear on this. Your child can go in the next morning.

You can buy mebendazole from a pharmacy for threadworms in adults and children aged 2 years or older. For children aged 6 months to 2 years, it is only available on prescription, so a toddler in the house means a call to the GP surgery for that one child, while everyone else is treated from the pharmacy.

Why does threadworm treatment fail?

This is where I can save you a second trip. Mebendazole kills the worms, but the NHS points out that it does not kill the eggs, and eggs can survive for up to 2 weeks on bedding, towels, toys and surfaces. If one of those eggs ends up on a finger and then in a mouth, the cycle starts again. That is why families who take the tablet but skip the hygiene routine often come back a month later convinced the medicine did not work.

For 2 weeks after treatment (or 6 weeks if someone cannot take the medicine), the NHS recommends:

• washing hands and scrubbing under fingernails, especially before eating and after the toilet
• a shower or bath every morning, to wash off eggs laid overnight
• keeping fingernails short, and discouraging nail-biting and thumb-sucking
• rinsing toothbrushes before use
• washing sleepwear, sheets, towels and soft toys on a hot wash every day for several days after treatment
• wiping kitchen and bathroom surfaces with hot water, and vacuuming and dusting with a damp cloth
• wearing underwear at night and changing it in the morning
• not shaking bedding or clothes, and not sharing towels or flannels

The morning shower is the one people underestimate. The eggs are laid around the bottom overnight, so washing first thing removes them before the day's scratching spreads them around the house.

Who should not just buy a tablet?

Mebendazole is safe for most people, but there are a few situations where I will stop and talk to you first:

• Children under 2. They need a prescription, so we will point you to the GP. Their older siblings and parents can still be treated from the pharmacy.
• Pregnancy. The NHS says mebendazole can be used in pregnancy if the benefits outweigh the risks, but a doctor may suggest hygiene measures alone first, particularly in early pregnancy. Speak to your GP or midwife. In the meantime, the NHS says threadworms can be treated with hygiene measures alone if they are kept up for 6 weeks.
• Breastfeeding. Mebendazole can often be used, as only small amounts pass into breast milk, but check with a pharmacist first.
• Other medicines. Tell us if you take metronidazole (an antibiotic) or cimetidine, as the NHS lists both as medicines that may not mix well with mebendazole.

We also ask whether anyone has travelled recently. Mebendazole is sold for threadworms only. Other worm infections, such as roundworm or hookworm, need a different dosing schedule and a prescription, so if the worms you have seen are much larger than a thread, or someone has been unwell after a trip abroad, that is a GP conversation.

A family we helped this autumn

A mum came in one weeknight in late September, about half past nine, with her coat over her pyjamas. Her 6-year-old had been scratching all week and she had finally spotted the worms with a torch. In the consultation room we went through the household: her, her partner, the 6-year-old, a 9-year-old, and an 18-month-old. She had been planning to treat just the one child.

We sold her enough mebendazole for the four eligible members of the house, explained that the baby would need a prescription and that she should ring the surgery in the morning, and wrote the hygiene list on the back of the bag, with "MORNING SHOWER" underlined. She came back three weeks later for something unrelated and told me nobody had itched since. The medicine was the easy part. The difference was treating everyone at once and doing the washing.

When to see a GP or call for help

Threadworms are a nuisance, not an emergency. But speak to a GP if:

• your child is under 2 and needs treatment
• you are pregnant
• symptoms have not started to improve a few days after treatment
• the worms keep coming back despite treating the whole household and following the hygiene routine
• you have seen larger worms, or someone is unwell after travel abroad

Serious side effects from mebendazole are rare. The NHS advises calling 999 if someone taking it has a seizure (fit) or signs of a severe allergic reaction, such as a swollen throat or tongue, a raised itchy rash, or difficulty breathing. Call 111 for other serious side effects, such as yellowing of the skin or eyes.

Threadworm treatment at Medway Pharmacy, Gillingham

We are at 465 Canterbury Street, Gillingham, ME7 5LJ, open Monday to Sunday from 7:30am to 10pm, excluding bank holidays. Threadworms have a habit of announcing themselves at bedtime, which is exactly when most pharmacies are closed, so our late opening hours are useful here. You do not need an appointment. Ask at the counter, or ask for the consultation room if you would rather talk privately. If you want to check we have the liquid in stock for a younger child, call us on 01634 575805 or use our contact page.