Overview
Also known as pinworms, threadworms (Enterobius vermicularis) are common parasitic worms that infest the human gut. Transmission occurs by the faecal-oral route when threadworm eggs are ingested.
Epidemiology
- Threadworm is the most common parasitic worm in the UK
- Around 20-30% of preschool and primary-school-aged children will have threadworm infestation
- Children aged 4-11 are most frequently affected
Presentation
Overview
Threadworm is asymptomatic in the majority of patients, however, some features include:
- Intense perianal itching that is worse at night
- Small, white, thread-like worms may be seen in the perianal skin or stools
- In female children, vulval irritation and itching may be present
Diagnosis
Overview
Most patients are diagnosed and treated clinically and empirically. If the diagnosis is uncertain, transparent tape can be applied to the perianal area first thing in the morning and sending it to a laboratory, where it is viewed under a microscope to detect threadworm eggs.
Management
Overview
The mainstay of treatment is an anthelmintic and hygiene measures for all members of the household, even if they have no symptoms:
- A single dose of mebendazole is first-line for children >6 months old
- For children aged 6 months and under, hygiene measures alone for 6 months are recommended
- For pregnancy/breastfeeding, mebendazole is contraindicated in the first trimester and the manufacturer recommends avoidance throughout pregnancy and caution when breastfeeding
Prognosis
- Reinfection is common
