Pinworm infection

DEFINITION

Pinworm infection is the most common type of intestinal worm infection in the United States and one of the most common worldwide. Pinworms are thin and white, measuring about 1/4 to 1/2 inch (about 5 to 13 millimeters) in length.

While the infected person sleeps, female pinworms lay thousands of eggs in the folds of skin surrounding the anus. Most people infected with pinworms have no symptoms, but some people experience anal itching and restless sleep.

Pinworm infection occurs most often in school-age children, and the microscopic eggs are easily spread from child to child. Treatment involves oral drugs that kill the pinworms and thorough washing of bedclothes, bed linens and underwear. For best results, the entire family should be treated.

CAUSES

Accidentally swallowing or breathing in pinworm eggs causes a pinworm infection. The microscopic eggs can be carried to your mouth by contaminated food, drink or your fingers. Once swallowed, the eggs hatch in the intestines and mature into adult worms within a few weeks.

Female pinworms move to the anal area to lay their eggs, which often results in anal itching. When 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, bed linens or toilet seats. The eggs can also be transferred from contaminated fingers to food, liquids, clothes or other people.

Pinworm eggs can survive for two to three weeks on surfaces.

SYMPTOMS

Symptoms of pinworm infection may include:

  • Itching of the anal or vaginal area
  • Insomnia, irritability and restlessness
  • Intermittent abdominal pain and nausea



Pinworms often cause no symptoms.

When to see a doctor

Consult your doctor if you have severe anal itching, especially at night.