Threadworms
Also known as Pinworms, Enterobiasis
This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.
What is threadworms?
Threadworms are small white worms that live in the bowel and lay eggs around the anus at night, causing intense itching. They are extremely common in children and are not a sign of poor hygiene. Everyone in the household must be treated at once, because eggs spread easily on hands and bedding.
Causes
- Enterobius vermicularis worms
- Swallowing eggs from contaminated hands, bedding or surfaces
- Scratching then transferring eggs to the mouth
- Eggs surviving up to two weeks on surfaces
Symptoms
- Intense itching around the anus, worse at night
- Disturbed sleep and irritability
- Tiny white thread like worms visible in stool or around the anus
- Itching around the vagina in girls
- Sometimes no symptoms at all
- Bedwetting in some children
Risk factors
- Age 4 to 11
- Attending nursery or school
- Household member with threadworms
- Nail biting and thumb sucking
- Crowded living conditions
Diagnosis
- Seeing worms around the anus, best checked a few hours after sleep
- Clear adhesive tape test applied to the skin in the morning
- Clinical diagnosis from typical night time itching
- No blood test is needed
Treatment
- Mebendazole for everyone in the household
- A second dose after two weeks if reinfection occurs
- Strict hygiene measures for two weeks alongside medication
- Treatment in pregnancy usually by hygiene measures alone
- Advice from a pharmacist for children under 2
Self care
- Treat everyone in the household on the same day
- Wash all bedding, nightwear and towels on a hot wash
- Vacuum and damp dust bedrooms thoroughly
- Bathe or shower first thing each morning to remove eggs
- Wash hands and scrub under nails after the toilet and before eating
- Keep nails short and discourage nail biting
- Wear close fitting underwear at night and change it every morning
When to see a doctor
Book an appointment if:
- Symptoms continuing after treatment and two weeks of hygiene measures
- Threadworms in a child under 2
- Pregnancy or breastfeeding
- Severe anal soreness or skin infection from scratching
- Weight loss or abdominal pain alongside
- Repeated reinfection despite thorough measures
Some symptoms need emergency care rather than an appointment. See the warning signs listed above.
Prevention
- Handwashing after the toilet and before meals
- Keeping fingernails short
- Morning showers during and after treatment
- Washing bedding and nightwear regularly
- Discouraging scratching and nail biting
- Treating the whole household together
Outlook
Threadworms are harmless and clear completely with treatment plus two weeks of careful hygiene. Reinfection is very common in families with young children, and repeated courses are sometimes needed. They cause no lasting damage.
Common questions
Why treat everyone if only one person has symptoms?
Many people carry threadworms without symptoms and continue shedding eggs, reinfecting the household. Treating everyone simultaneously is the only way to break the cycle.
Why shower in the morning?
Eggs are laid around the anus overnight. A morning shower washes them away before they spread to hands, clothing and surfaces during the day.
References
Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.