A pinworm infection is one of the most common worm infections worldwide. Pinworms are thin and white. They're about 1/4 to 1/2 inch — about 6 to 13 millimeters — long.
Pinworm infections are caused by swallowing or breathing in pinworm eggs. These tiny eggs are too small to see with the eyes. Infection happens most often in school-age and preschool-age children.
Symptoms of a pinworm infection can include anal itching and restless sleep. That's because when their hosts sleep, female pinworms lay thousands of eggs in the folds of skin that surround the anus. But many people with pinworm infections have no symptoms.
Treatment for a pinworm infection involves taking anti-parasite medicines that kill the pinworms. For best results, everyone in the family of the person with the infection should be treated. All bedding, pajamas and underwear should be washed in hot water too.
Help prevent pinworm infections by bathing often and washing hands regularly. Wash laundry such as bedsheets and underwear in hot water. Keep fingernails short and don't scratch the anal area.
Symptoms of a pinworm infection can include:
But pinworm infections often cause no symptoms.
Talk with your healthcare professional if you or your child has serious anal itching, especially at night.
Most often, swallowing pinworm eggs causes a pinworm infection. The eggs spread through stool. This can be carried to the mouth by tainted food or drink or by unwashed fingers. Once swallowed, the eggs hatch in the small intestine. They grow into adult worms within a few weeks.
Female pinworms move to the anal area to lay their eggs. This often causes anal itching. If you scratch the itchy area, the eggs cling to your fingers and get under your fingernails. The eggs then get transferred to other surfaces, such as toys, bedding or toilet seats. The eggs also can be transferred from fingers to food, liquids, clothes or other people.
Pinworm eggs can survive on surfaces indoors for 2 to 3 weeks.
Much less often, pinworm eggs get into the air and are inhaled and swallowed.
Risk factors for a pinworm infection include:
Most often, pinworm infections don't cause serious problems called complications. Rarely, having many pinworms in the body can cause infection of female genitals. The worms can travel from the anal area to the vagina.
Other rare complications of a pinworm infection can include:
You can take the following steps to help prevent a pinworm infection. If you've had a recent infection, these steps also can help lower the risk of another one:
Your healthcare professional can find a pinworm infection by checking for the worms or eggs. An exam of the anal area and underwear may be done during your appointment to look for worms. Or, if your small child might have an infection, you may be told to check these areas at night. Check 2 to 3 hours after your child goes to sleep.
Another test that can be done at home is called the tape test. In general, you need see-through cellophane tape to do the test. Press the sticky side to the skin around the anus after waking up and before bathing or using the toilet. If eggs are present, they stick to the tape. Ask your healthcare professional for complete instructions, including the exact type of tape to use and how to store it after the test.
For best results, do the tape test three days in a row. Then take the pieces of tape to your healthcare checkup. Your health professional can look at the tape under a microscope to see if there are any pinworm eggs.
Your healthcare professional also might collect samples from under your fingernails. A lab checks the samples for eggs.
Treatment for a pinworm infection involves taking anti-parasite medicine that helps kill the worms. Your healthcare professional may recommend that you and any other people in your home take the medicine.
One type of medicine called pyrantel pamoate is sold without a prescription. It's the preferred treatment for pregnant people and children under 2 years old.
The most common prescription anti-parasite medicines for pinworms are:
No matter what medicine you're given, you take a second dose two weeks later. This helps kill worms that hatched from any eggs that were present after the first dose.
You may have mild digestive side effects during treatment. Along with following your treatment, be sure to wash all bedding and clothes.
When you call to make an appointment, ask your healthcare professional if you should do the tape test. The test involves pressing the sticky side of a piece of see-through tape to the skin around the anus. This is done on the person you suspect has pinworms as soon as the person wakes up in the morning. The eggs stick to the tape.
You then take the tape to your appointment so the healthcare professional can look for pinworms or eggs under a microscope.
Write a list of questions for your healthcare professional too. This can help you make the most of your time together. For a pinworm infection, some basic questions to ask include:
Your healthcare professional is likely to ask you questions such as:
If you have anal itching, try not to scratch.
