Pinworm Infection in Kids

Dealing With Itchy Bottoms and Sleepless Nights

Mother with her toddler on the potty
Ryan McVay/Photodisc/Getty Images

Pinworm infection (known clinically as enterobiasis or oxyuriasis) is a diagnosis most any parent would cringe to hear. Pinworms (Enterobius vermicularis), sometimes called threadworms or seatworms, are small, thin, parasitic nematodes (roundworms). They like to live in the colon and the rectum of humans, causing anal itching that's especially troublesome at night, making it hard to sleep. Though bound to be unpleasant, pinworm infection is not a serious health threat and can easily be treated.

Pinworm infection is the most common intestinal infection in the world, according to the Centers for Disease Control and Prevention (CDC). It mostly affects preschoolers and school-aged children, but people who live in institutions or those who care for someone with pinworms also are at high risk. In fact, enterobiasis is highly contagious, so if one person in a household has a pinworm infection, it can easily spread to others unless care is taken to prevent that from happening.

How Pinworm Infection Spreads

A person becomes infected with pinworms by ingesting or breathing in their microscopic eggs. This usually happens after an individual touch an object that's contaminated with the eggs and then brings their hands close to their mouth or nose or transfers eggs to food or drink. The eggs can live anywhere—bed linens, towels, clothing, toilets, bathroom fixtures, toys and sandboxes, kitchen counters and utensils, classroom desks, and school lunch tables. They do not, however, live on animals, so you can't get pinworms from your dog or cat (or pass the parasite along to a pet if you're infected). 

Once the eggs are inside the body, they travel to the small intestine to hatch; the larvae that result move on to the large intestine where they live as a parasite while maturing. After a month or two, adult female pinworms take yet another trip, this time to the area around the rectum, to lay eggs and then die. The total lifespan of a pinworm is about 13 weeks.

Despite being too tiny to be seen, the eggs trigger tremendous itching in the perianal area. A child who scratches his bottom can easily pick up pinworm eggs on his fingers. If he brings his fingers to his mouth he could ingest the eggs, setting off a new pinworm lifecycle. He also could pass eggs along to someone else by touching them directly or by touching a surface that someone else later comes in contact with. Note that pinworm eggs can live on surfaces outside of the body for as many as two to three weeks.

Symptoms and Complications

The classic symptom of pinworm infection is rectal itching. It's usually worse at night and often irritating enough to interfere with sleep, leaving kids tired and irritable.

In little girls, pinworms can cause vaginal itching and even some discharge. There even have been case reports of pinworms in the female reproductive tract leading to complications such as urinary tract infections, vaginitis, and even endometriosis.

Kids of both genders can develop a rash in the genital area.

If a child is really itchy and scratches enough to break the skin on his bottom, he could develop a bacterial infection. 

Note, though, that there are other potential causes of rectal and vaginal itching. Poor hygiene (not wiping thoroughly after a bowel movement) is one. Another is an illness called perianal cellulitis, which is caused by the strep bacteria. If your child is diagnosed with pinworm but doesn't respond to treatment, his doctor may test him for strep. Perianal cellulitis is treated with antibiotics.

Bedwetting is another possible symptom of enterobiasis if the worms manage to irritate the urethra—the channel by which urine leaves the bladder and passes out of the body.

Weight loss can occur if pinworms go undetected or untreated for a long period of time. Pinworms are parasites, which means they leech essential nutrients from the body. Sometimes, pinworms cause digestive symptoms such as abdominal pain or nausea.

Checking for Pinworms

If you think your child has pinworms, you may be able to confirm your suspicions by looking at his stool. You also can check his bottom or underwear at night; wait a few hours after he goes to sleep and use a flashlight. You'll be looking for tiny, white, half-inch-long worms that resemble bits of thread. Be patient: It may take several evenings to actually spy a worm. 

Another way to check for pinworms is with a tape test. Your doctor may give you the materials for this or a special kit that contains them. Here are the steps:

  1. In the morning, before your child has a bath, press the sticky side of an inch-long piece of clear tape against your child's anal area. Hold it there for a few seconds to give the worms time to adhere firmly to the tape. 
  2. Transfer the tape sticky-side down to a glass slide, place the slide in a clean plastic bag. Seal the bag and wash your hands.
  3. You can repeat the test on three separate days to be certain you pick up any existing pinworms. When you feel confident you've captured enough pinworms, take the slides to your doctor for examination.

Treatment and Prevention

Pinworm is treated with medication that literally kills the worms. There are several prescription medications for treating pinworm infection, such as Emverm (mebendazole) and Albenza (albendazole). Both can be very expensive.

Fortunately, there are over-the-counter medications that can effectively cure pinworm infection that cost considerably less money. One of these is Reese's Pinworm Medicine (pyrantel pamoate), which comes as a liquid and is safe for kids ages 2 and up. You also can sometimes find this medication sold under a drugstore brand, such as CVS.

In addition to using medication to get rid of the infection, there are measures you should take to prevent it from spreading. These include:

  • Cutting a child's nails very short so that he doesn't scrape open his skin when scratching.
  • Making sure everyone in the household washes their hands frequently with warm, soapy water.
  • Washing all clothing, bed linens, and towels that might have had contact with the pinworms in hot water. Don't shake these items out before they've been washed. 
  • Wiping down any surfaces or items such as toys that could be harboring pinworm eggs.
  • Vacuuming all carpets.
  • Keeping rooms well-lit during the day, as pinworm eggs are sensitive to light.
  • Bathing children separately and daily.
  • Washing kids' pajamas every few days and, of course, putting clean underwear on them every day.

It may take a little time and effort, but by following these strategies you should be able to get your household free of pinworms within a few weeks.

Was this page helpful?

Article Sources