How to tell if you have pinworms or threadworms

Updated March 23, 2017

Pinworms, also called threadworms and seatworms, are parasites that infect the body when you unknowingly touch their eggs and ingest them. MedlinePlus says female threadworms infect the body by travelling through the digestive tract and laying eggs near the anus and vaginal region. KidsHealth says threadworms (pinworms) look like small, white, thin pieces of thread, but the eggs are too small to see without a microscope. Though children commonly get threadworms, adults are also susceptible because they transfer from person to person and from touching infected items. Threadworm infections are often asymptomatic; however, you can experience a few uncomfortable symptoms.

Check for rashes caused by scratching and skin irritations. Threadworms cause itching in the anus and vaginal region, according to the National Institute of Allergy and Infectious Diseases (NIAID). Itching usually occurs at night, making it hard to get a good night's sleep and causing skin rashes from constant scratching. If you can't see your backside, get someone to assist you in checking the area.

Look for worms in the toilet and in your underwear. KidsHealth says threadworms live in the intestine and colon and leave the body via the digestive tract. If you have a threadworm infection, you will see worms in the toilet after using the restroom. The parasites also appear on your underwear when you wake up in the morning.

Perform the torch test at night. PubMed Health suggests doing the torch test as the first diagnostic tool to check for threadworms. You need to shine a torch in the rectal area to see if worms come out of the opening. If you don't see worms the first time you take the test, do it two or three more times to make sure no worms appear.

Take the tape test to check for the presence of threadworm eggs. PubMed Health says to take a 2.5 cm (1-inch) piece of sticky tape and press the sticky side on the anus. Transfer the tape to a glass slide, with the sticky side facing down. You may have to do the test two or three times before you get a significant number of eggs.

Bring the slide to your doctor so he can examine the sample under a microscope. Be prepared to tell your doctor how long you've experienced itching, the magnitude of your symptoms and if symptoms occur at night. Mayo Clinic says doctors will want to know if you are around children and if other family members have the same symptoms.


If one person in the family has an infection, everyone in the household needs treatment to get rid of worms and prevent them from returning. Talk to your doctor about medications and prescription drugs for mild infections that are available at your local pharmacist.

Take a shower to reduce the amount of eggs surrounding the anus.

Parents should cut their children's fingernails to discourage scratching and getting eggs under the fingers.

Practice good hygiene to prevent infections, including washing hands after using the bathroom and before eating and not biting nails.

You should wash sheets, clothing, towels and other cloth items in hot water to kill any remaining eggs.

Things You'll Need

  • Torch
  • Sticky tape
  • Glass slide
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About the Author

Based in Tucson, Ariz., Cicely A. Richard has been writing since 1996. Her articles have been published in the “Arizona Daily Star” newspaper and “ForeWord Magazine.” Richard earned Bachelor of Arts degrees in English and journalism from Louisiana State University. .