What are threadworms?
Threadworms (pinworms) are the most common parasitic worms found in temperate countries and usually affect children.
The worms can be spread by children sucking objects or eating food which is contaminated by threadworm eggs. Threadworms are parasites which live in the intestines, but at night the females come out of the rectum to lay their eggs on the skin around the anus. These eggs can cause itching and sometimes inflammation as a result of the person scratching the area constantly. Eggs on the fingers or under the nails can then be transferred to the mouth of the sufferer or other persons, maintaining or spreading the infection. The eggs may also survive in dust for up to two weeks and may be passed on if the dust is inhaled.
If a child has threadworms it is usual for the whole family to be treated as other members may also be infested even if they do not have any symptoms.
The tiny worms, like threads of cotton, may be seen moving on faeces. You may be asked to apply a piece of clear adhesive tape to the skin near the anus. Threadworm eggs will stick to it, and can be seen under the microscope.
What treatment is available?
Threadworms are usually treated with mebendazole. Mebendazole may be prescribed as Vermox® or bought over the counter from a pharmacist as Ovex®. With these treatments, patients are often advised to repeat the dose after 14 days to help prevent re-infection.
- Ensure you always wash your hands after going to the toilet and before meals
- Shower daily to remove any eggs from the anal area, change underwear daily and bedding regularly
- Keep fingernails short, ideally children should wear cotton gloves to bed
- Keep your house as dust-free as possible
- Treat the whole family on the same day to avoid reinfection
Fact sheet provided by MIMS
Date last reviewed: February 2008