Pinworm Infection

Pinworm infections are caused by a small, white intestinal worm Enterobius vermicularis. Pinworms are about the length of a staple and live in the intestines of humans; they do not live in any other species. While an infected person sleeps, female pinworms leave the intestines through the anus and deposit large numbers of eggs on the surrounding skin.

Contents 1 Other Names 2 Symptoms 3 Diagnosis 4 Treatment 5 Cures 6 Prevention 7 Chances of Developing 7.1 Risk Factors 8 How is pinworm infection spread? 9 Prognosis 10 References

Other Names

• Enterobiasis
• Seatworm infection
• Oxyuriasis

Symptoms

Itching around the anus, disturbed sleep, and irritability are common symptoms. If the infection is heavy, symptoms may also include loss of appetite, restlessness, and difficulty sleeping. Symptoms are caused by the female pinworm laying her eggs. In females, the itching may spread to the vagina. Most symptoms of pinworm infection are mild. Many infected people have no symptoms.

Diagnosis

If pinworms are suspected, transparent adhesive tape (often called the "cellophane tape test") or a pinworm paddle (which can be obtained from a healthcare provider) are applied to the anal region. The eggs become glued to the sticky tape or paddle and are identified by examination under a microscope. Because bathing or having a bowel movement may remove eggs, the test should be done upon waking up in the morning. A sample may be needed by a health care provider for examination. Since scratching of the anal area is common, samples taken from under the fingernails may also contain eggs. Eggs are rarely found during lab examinations of stool or urine. At night, the adult worms can sometimes be seen directly in bedclothes or around the anal area.^[1]

Treatment

Treatment is with either prescription or over-the-counter drugs. Most healthcare providers recommended seeking medical advice before treating pinworm. Treatment involves a two-dose course. The second dose is given two weeks after the first.

Usually a single tablet of mebendazole (marketed as Vermox) is used for treatment. If the infection continues, the dose can be repeated, if necessary. Another effective medication is albendazole (marketed as Valbazen). If the pinworm infection has spread to internal urinary and genital structures, a combination therapy is given which consists of oral mebendazole and ivermectin for the worms as well as topical therapy applied to the skin to kill the eggs.

Itching can be relieved by sitting in shallow warm baths to which salt or Epsom salts have been added. Ointments containing zinc oxide or regular petroleum jelly may also provide some relief.

Cures

If the infection recurs, the infected person is treated with the same two-dose treatment. Close family contacts often need to be treated. If the infection occurs again, it is important to search for the source of the infection. Playmates, schoolmates, close contacts outside the house, and household members are likely sources of re-infection. Each infected person needs to receive the usual two-dose treatment. In some cases it may be necessary to treat with more than two doses. One option is four to six treatments spaced two weeks apart.

Prevention

Pinworm infection can prevented by:

• Bathing after waking up to help reduce the egg contamination.
• Changing and washing underwear each day. Frequent changing of night clothes is recommended.
• Changing underwear, night clothes, and sheets after each treatment. Because the eggs are sensitive to sunlight, opening blinds or curtains in bedrooms during the day is helpful.
• Personal hygiene is important, including washing hands after going to the toilet, before eating and after changing diapers.
• Trimming fingernails short.
• Discouraging nail-biting and scratching bare anal areas. These practices help reduce the risk of continuous self reinfection.

Cleaning and vacuuming the entire house or washing sheets every day are probably not necessary or effective. Screening for pinworm infection in schools or institutions is rarely recommended. Children may return to day care after the first treatment dose, after bathing, and after trimming and scrubbing nails.

Chances of Developing

Risk Factors

Pinworm is the most common worm infection in the United States, with about 10% of the population in the US carrying the organism and about 200 million affected people worldwide. School-age children, followed by preschoolers, have the highest rates of infection. In some groups nearly 50% of children are infected. Infection often occurs in more than one family member. Adults are less likely to have pinworm infection, except mothers of infected children. Child care centers, and other institutional settings often have cases of pinworm infection.

How is pinworm infection spread?

Pinworm eggs are infective within a few hours after being deposited on the skin. They can survive up to two weeks on clothing, bedding, or other objects. People can become infected after accidentally ingesting (swallowing) infective pinworm eggs from contaminated surfaces or fingers.

Prognosis

Pinworms usually cause very little damage and can be eradicated easily with proper treatment; full recovery is the expected outcome. Reinfestation is unfortunately common.

References

1. ↑ Kucik CJ, Martin GL, Sortor BV. Common intestinal parasites. Am Fam Physician. 2004 Mar 1;69(5):1161-8. Abstract | Full Text | PDF