Pinworms (Roundworms)


Symptom Is Anal Itching

There are several types of roundworms that can cause infection in humans. In the U.S., the pinworm is the most common worm parasite. Pinworm eggs enter the body when they are inhaled or when finger nails (after scratching the infected area) are put in the mouth. Infections do not usually cause serious problems but they are marked by persistent itching, mostly at night-time. Pinworm is easily treated by a single dose of medication, repeated in two weeks to prevent recurrence. When one person is infected, all other family members should be treated.

The usual symptom of pinworm is itching in the anal area where pinworms lay their eggs.

Pinworm Infection

Pinworms, also called roundworms, are common sources of infection in humans. In the United States, pinworm infections are found in more than 42 million persons. Infections can occur anywhere, and in all social classes. Pinworm is especially common in children from ages 5 through 14. Pinworm infections are not usually serious but they are annoying and cause itching which keeps people awake at night. Pinworms are easily spread in congested living areas, institutions, gymnasiums and within families. The pinworm’s lifespan is short, so infections that continue over a period of time are a result of reinfection.

How Pinworms Spread: Pregnant females live an average of 11-35 days in the intestinal tract. They migrate to the anal area at night and lay an average of 11,000 eggs which cause anal itching. The eggs become embryos within six hours. The resulting embryos remain infective for 20 clays on bedsheets, pajamas, in dust or air and can get under the fingernails if the area is scratched. Pinworm eggs are swallowed when fingernails that have scratched the anal area are put into the mouth, or when eggs are inhaled after contaminated bedclothes or underwear is shaken. The embryos hatch in the duodenum and develop into adults in the abdomen. The lifecycle is repeated when the pregnant female travels from the colon to the anal area to lay more eggs.

Symptoms: A large number of people infested with pinworm do not realize they are infected because they have no symptoms. Those people with symptoms commonly complain of anal itching, especially at nighttime. The itching may be mild or severe. Sometimes, inflammation may occur in the vagina and a discharge or peritonitis (inflammation in the abdominal area) may occur if the adult worms follow a different path from the gastrointestinal tract. Rarely, a pinworm infection can develop in the appendix or other areas of the intestines, such as the small or large bowel.

Treatment: A simple test can be done to identify a pinworm infection. The test is done early in the morning. A piece of cellophane adhesive tape is pressed against the anal area. Pinworm eggs will be visible under a microscope. A repeat of the test over one to three mornings will confirm the presence of 99% of pinworm infections. The treatment is one dose of the drugs Antiminth (pyrantel pamoate) or Vermox (mebendazole) taken by mouth. Vermox is usually not recommended for use in pregnant women or children under 2 years of age. Because these drugs do not destroy the eggs, the single dose is repeated in two weeks to eliminate any reinfection. No other special precautions are necessary for treatment, but washing underwear and bedsheets may be recommended. Family members who have pinworms must also be treated to prevent continuing infections. Some doctors recommend treating all family members, even if they have no symptoms of infection because of the fact that symptoms are not always present. Some diarrhea or abdominal cramping may occur after drug treatment, especially when large numbers of worms are expelled. Pinworm infection is very common and is easily treated. If you have any questions about the infection or ways to treat it, ask your pharmacist.

US Pharmacist
Copyright 2003 Jobson Publishing, LLC