Pinworms Cause Anus and Vaginal Itching and Can Spread Easily Between People

Pinworms are one of a number of parasitic worms that can infect the human body and are a common condition. Itching in the anal or vaginal area is the most common indication of pinworm infection. In medical terms, anal itching is referred to as anal pruritus.

There are a lot of scary diagnoses out there, but having worms living in your anus? That has to take the cake.

A Case Study

A report in the New England Journal of Medicine (NEJM) tells the tale of a 32-year-old woman who went to the doctor complaining of anal itching and bleeding for about two months. Doctors performed a colonoscopy to see what was going on, and lo and behold, they found a mama pinworm carrying eggs. *shudders*

Apparently, the woman's 5-year-old daughter had classmates who had recently been diagnosed with pinworms, and the daughter had been experiencing anal itching, too.

How Pinworms Spread

While this sounds like a terrifying diagnosis, it's actually more common than you think, especially in children. Pinworm infection, caused by a white roundworm with the scientific name Enterobius vermicularis, is the most common type of intestinal worm infection in the US, according to the Mayo Clinic. As many as 50% of kids pick up the infection, the Centers for Disease Control and Prevention (CDC) reports.

People catch these parasites by accidentally swallowing their eggs.

"When people who are infected touch their anus, the eggs attach to their fingertips," the US Library of Medicine explains. "They can spread the eggs to others directly through their hands, or through contaminated clothing, bedding, food, or other articles."

Then, once the eggs hatch, the pinworms make themselves at home in the colon and rectum, and female pinworms lay eggs on the skin around the anus while a person sleeps. Cue itching around the anus or vagina.


The CDC states that the medication used to treat pinworms is not effective on pinworms eggs so a second treatment is required about 2 months after the first treatment to destroy newly hatched worms.

MedlinePlus tells us that when treatment is necessary the entire household must take the treatment. Treating everyone avoids reinfection. Other actions to avoid infection or reinfection include:

  • Showering or bathing when you wake up
  • Avoid biting your nails
  • Don't scratch your anus
  • Change your underwear daily
  • Regularly wash your sheets and pajamas
  • Wash your hands after changing diapers or using the bathroom
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