What is a pinworm infection?

Pinworm infection is caused by the helminth (Enterobius vermicularis), a small, white parasitic worm. The pinworm is about the length of a staple (ranges from 2 to 13 mm [0.08 to 0.5 inches]) and lives for the most part in the rectum of humans. While an infected person is asleep, female pinworms exit the intestines through the anus and deposit eggs on the skin around the anus. Within a few hours of being deposited on the skin around the anus, pinworm eggs become infectious (capable of infecting another person). Pinworm eggs can survive up to three weeks on clothing, bedding, or other objects if the environment is sufficiently moist.
What is the pinworm test?
If pinworms are suspected, transparent adhesive tape or a pinworm paddle (supplied by your healthcare provider) is applied to the anal region. The tape can pick up both eggs and occasionally the adult worms. Most clinicians suggest the test be done as soon as the person awakens and before any bowel movement or cleansing (bath, shower) as these actions tend to remove the eggs and parasites from the anal/rectal area.
The pinworm eggs or a few adult worms adhere to the sticky tape or paddle and are identified by examination under an ordinary microscope by a qualified laboratory technician.
In some individuals, it is possible to see the adult worms without a microscope, but the transparent eggs are small and can only be seen with a microscope.
When should the pinworm test be done?
The test should be done as soon as you wake up in the morning (because bathing or having a bowel movement may remove eggs). The exam may require several samples for a positive diagnosis. Researchers suggest that repeating the test at about three different intervals yields about a 90% detection rate.
Aside from the anal region, what other area can be tested for pinworms?
Samples taken from under the fingernails may also contain eggs (since scratching of the anal area is common).
Can I see the pinworms myself?
At night, the adult worms can sometimes be seen directly on the bedclothes or around the anal area. The best time for observation is at night when itching in the anal/rectal area awakens a person; it is likely the sensation caused by migrating female worms depositing eggs and irritating the skin (see the following section).
What do pinworms look like?
The pinworms are white, can be seen with the naked eye (no magnification) and are about the length of a staple (about 8-13 mm for female and 2-5mm for male worms). The eggs that are laid by the female worms are not visible as they are about 55 micrometers in diameter and are translucent (see Figure 1).
The male and female worms live for the most part within the rectum of humans but have a life cycle in humans that involves rectal/oral transmission (see Figure 2).

While an infected person is asleep, female pinworms leave the intestines through the anus and deposit eggs on the skin around the anus. This causes itching and irritation of the surrounding area; children especially will scratch the rectal/anal area, get eggs on their fingers or underneath their fingernails and transport the infective eggs to bedding, toys, other humans, or back to themselves. The eggs hatch into larval forms in the small intestines and then progress to the large intestine where they mature, mate, and progress to the rectal/anal area where females deposit about 10 to 15 thousand eggs.

SLIDESHOW
Pinworms Symptoms, Treatments, and Medication See SlideshowHealth Solutions From Our Sponsors
REFERENCE:
"Parasites - Enterobiasis." CDC.gov. <http://www.cdc.gov/parasites/pinworm/>.
Jeandron A, Abdylaeva G, Usubalieva J et al., Accuracy of the Kato-Katz, adhesive tape and FLTOTAC techniques for helminth diagnosis among children in Kyrgyzstan, ACTA Trop., 116(3):185-192, 2010.
Previous contributing author: Robert Ferry Jr., MD
Top Pinworm Test Related Articles
albendazole
Albendazole is an anthelmintic medication used to treat infections of tapeworm larvae (parasitic worms). Common side effects of albendazole include abnormal liver function tests, abdominal pain, nausea, vomiting, and headache. Albendazole should be used during pregnancy only if the potential benefit outweighs potential fetal risks, and if no alternative treatment is available. It is not known if albendazole is present in breast milk, however, it is present in animal milk; use with caution in nursing mothers because many drugs are excreted in breast milk.How to Stop Anal Itching
Anal itching is the irritation of the skin at the exit of the rectum, known as the anus, accompanied by the desire to scratch. Causes include everything from irritating foods we eat, to certain diseases, and infections. Treatment options include over-the-counter medications, using moist pads, and gentle cleaning and drying of the anus.Children's Health
Children's health is focused on the well-being of children from conception through adolescence. There are many aspects of children's health, including growth and development, illnesses, injuries, behavior, mental illness, family health, and community health.diethylcarbamazine
Diethylcarbamazine belongs to a class of medications known as anthelmintics used to treat filarial diseases caused by parasitic worm infections. Side effects of diethylcarbamazine include dizziness, headache, fever, joint pain (arthralgia), muscle pain (myalgia), nausea, and vomiting. Use with caution in patients with cardiac disorders or renal impairment. Do not use diethylcarbamazine during pregnancy or while breastfeeding. Diethylcarbamazine is not commercially available in the U.S.ivermectin
Ivermectin is an antiworm (anthelmintic) medication used to treat intestinal strongyloidiasis and river blindness (onchocerciasis), types of diseases caused by parasitic roundworm (nematode) infestations. The FDA has not authorized or approved ivermectin for the treatment or prevention of COVID-19. Common side effects of ivermectin include itching, rash, hives (urticaria), skin (swelling) edema, fever, joint pain (arthralgia), inflammation of the synovial membrane on joints (synovitis), enlargement and tenderness of lymph nodes, and eye inflammation. Avoid use or use with caution if pregnant or breastfeeding.mebendazole
Mebendazole is a medication prescribed to treat pork worms, tapeworms, roundworms, hookworms, threadworms, pinworms, and whipworms. Side effects of mebendazole include abdominal pain, diarrhea, dizziness, drowsiness, headache, vomiting, chills, itching, flushing, hiccups, ringing in the ears, low blood pressure, bloody urine, and a drop in the number of blood cells. Consult your doctor if pregnant or breastfeeding.melarsoprol
Melarsoprol is a medication administered intravenously to treat human African trypanosomiasis, also known as sleeping sickness. Melarsoprol is a highly toxic drug derived from arsenic, with severe side effects, and hence is used only for the treatment of the second stage of African trypanosomiasis with involvement of the central nervous system. Melarsoprol kills the parasites that cause sleeping sickness. Common side effects of melarsoprol include high blood pressure (hypertension), cardiac insufficiency, heart muscle (myocardial) damage, headache, high temperature (hyperthermia), brain disease (encephalopathy), peripheral nerve disease (neuropathy), nausea, vomiting, diarrhea, bloody stools, and others. Do not take if pregnant.Pinworms in Children and Adults
Pinworm infection is an intestinal infection caused by a pinworm, seatworm, or threadworm. Female pinworms leave the intestine through the ankus and deposit eggs on the skin around the anus while a person is asleep. Pinworm infection is the most common worm infection in the U.S. Symptoms include anal itching or vaginal itching. Pinworm infection is generally spread by inadequate handwashing from infected persons. Treatment is effective after a diagnosis is made with a pinworm test.Pinworms Slideshow
Pinworm symptoms include itching and redness around the anus. Pinworm infection is common in children and adults. Pinworms are treated with over-the-counter medication. Your doctor can help confirm the diagnosis by checking for the presence of pinworms in stool.suramin
Suramin is a medication intravenously (IV) administered to treat sleeping sickness, also known as African trypanosomiasis caused by microscopic parasites of the species Trypanosoma brucei. Suramin may cause severe hypersensitivity reactions including shock and loss of consciousness. Common side effects of suramin include shock, dizziness, fatigue, headache, loss of consciousness, peripheral nerve damage (neuropathy), numbness, tingling (paresthesia), nausea, diarrhea, vomiting, oral inflammation (stomatitis), and others. Consult your doctor if pregnant or breastfeeding.