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Pinworms (cont.)

Pinworms Symptoms

Many people have pinworms and don't have any symptoms at all.

  • The most common symptom of pinworms is itching around the anus. It is worse at night when the female worm deposits her eggs on the person infected. This can lead to difficulty getting a good night's sleep. This intense itching is felt to be due to an inflammatory response to the adult worm and her eggs in the perianal tissue. If severe scratching occurs, the skin may break down and allow development of a secondary bacterial infection.
  • Pinworms can rarely migrate into the vagina or urinary tract causing irritation in these regions. Intense itching is again the prominent complaint. This location of infection is less common than the perianal region, and the infection usually goes away on its own. Case reports of E. vermicularis migration into the internal female reproductive tract have been reported. These infections are very rare.
  • Pinworms do not cause abdominal pain, bloody bowel movements,fevers, or poor appetite. If the person has any of these signs or symptoms, they may have a more serious condition and should call a doctor or visit the hospital's emergency department. Adult pinworms have been found in inflamed appendices removed at operation; however, whether the pinworm infection was the cause of appendicitis is controversial.

When to Seek Medical Care

If you suspect that you or your child might have pinworms, you should make an appointment to see your doctor.

To help the doctor make the diagnosis, look for these signs:

  • Pinworms are big enough to be seen with the naked eye. They are yellow-white and look like a fine piece of thread. They are usually less than one-half inch long.
  • Pinworms are most active at night. The best time to see them on the anus is a few hours after bedtime. Parents sometimes try to sneak up on the worms by throwing back the child's bedcovers and shining a flashlight on a bare bottom in hopes of catching the culprits in action.
  • Pinworms can also sometimes be seen on the outside of a child's stool.

Pinworm Diagnosis

  • If a person suspects pinworms but does not see them, the "Scotch tape test" can be used.
    • It is best done at night during the characteristic intense itching or early in the morning before any bathing or washing.
    • Wrap a piece of cellophane tape around a tongue depressor, sticky side out, and press it to the skin around the anus to collect any eggs.
    • Take the tape to a doctor, who will put it under a microscope to look for pinworm eggs.
    • The doctor may ask the person to use several pieces of tape to increase the likelihood of seeing the eggs. A single specimen will detect approximately 50% of cases; 90% of cases will be detected if the test is repeated three times.
    • Blood tests are not necessary to establish the diagnosis of pinworm infection.
  • The doctor may decide based upon the patient's symptoms that pinworms are present and may treat with medication without doing any tests.
  • If one person in a household has pinworms and other people in the household have the same symptoms, it is not necessary to test everyone before treating.
Medically Reviewed by a Doctor on 6/19/2015

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Read What Your Physician is Reading on Medscape

Pinworm »

Pinworm, or Enterobius vermicularis, is prevalent throughout the temperate regions of the world and is the most common helminthic infection in the United States.

Read More on Medscape Reference »

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