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Pinworm infection
By Mayo Clinic staffOriginal Article: http://www.mayoclinic.com/health/pinworm/DS00687
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Definition
Pinworm infection is the most common type of intestinal worm infection in the United States. Pinworms are thin and white, measuring about 1/4 inch to 1/2 inch (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. While most people infected with pinworms have no symptoms, some people experience anal itching and restless sleep.
Pinworm infection occurs most frequently in school-age children, and the microscopic eggs are easily spread from child to child — especially if children scratch their bottoms or neglect to wash their hands after using the bathroom or before eating.
Treatment involves oral drugs that kill the pinworms. For best results, the entire family should be treated at the same time.
Symptoms
Symptoms of pinworm infection may include:
- Itching of the anal or vaginal area
- Insomnia, irritability and restlessness
- Intermittent abdominal pain and nausea
Some people with pinworms have no symptoms.
When to see a doctor
Consult your doctor if you have mild abdominal pain along with insomnia or irritability, or you're experiencing consistent or severe anal or vaginal itching.
Causes
You acquire a pinworm infection by accidentally swallowing pinworm eggs. The microscopic eggs can be carried to your mouth by contaminated food, drink or fingers. Once swallowed, the eggs hatch in the intestines and mature into adult worms within a few weeks.
Female worms crawl outside the anus to lay their eggs, which often results in anal itching. When a person scratches the itchy area, the eggs cling to fingers and are then transferred to other surfaces, such as toys or bedclothes. The eggs can also be transferred from contaminated fingers to food, liquids or other people.
Pinworm eggs can survive for two to three weeks on surfaces. You can become infected with pinworms if you consume contaminated food or drink, or if you touch a contaminated surface and then touch your mouth.
Risk factors
Risk factors for pinworm infection include:
- Age. Pinworm infections are most likely to occur in children between the ages of 5 and 10. The microscopic eggs are easily spread to family members, caregivers, or other children at school or child care centers.
- Crowded living spaces. People who live in institutions are at higher risk of developing pinworm infections.
- Temperate climate. While pinworms occur worldwide, they are more common in nontropical countries.
Complications
Typical pinworm infections don't cause serious problems. In rare circumstances, heavy infestations may cause:
- Urinary tract infection. More common in females, urinary tract infections sometimes are caused by heavy pinworm infestation.
- Infection of the peritoneal cavity. In women or girls, the parasite may travel from the anal area up the vagina to the uterus, fallopian tubes and the area around the pelvic organs. This can cause vaginitis, endometritis or other problems.
- Weight loss. When a large number of adult pinworms are living in your intestines, they can cause abdominal pain and take enough nutrients that you will lose weight.
Preparing for your appointment
What you can do
You may want to prepare a list of answers to the following questions:
- When did the itching start?
- Does it occur mostly at night?
- Is there anything that makes the symptoms better or worse?
- Are other family members having similar symptoms?
- Do you know if you or your child has had contact with someone who has pinworms?
- Have you found any dead worms in bedclothes, underwear or in the toilet?
You may also want use clear cellophane tape to take samples from the anal area as soon as the infected person wakes up — before any trips to the bathroom. Your doctor can look at the tape under a microscope to see if there are any pinworm eggs.
What to expect from your doctor
During the exam, your doctor may also perform the cellophane tape test to check for pinworm eggs under a microscope.
Treatments and drugs
Mild pinworm infection, or an infection with no symptoms, may never need treatment. If treatment is needed, your doctor may prescribe medication to all members of your household to prevent infection and reinfection. The most common anti-parasite medications for pinworms are:
- Mebendazole (Vermox)
- Albendazole (Albenza)
- Pyrantel (Pin-X, others)
You may have mild gastrointestinal side effects during the course of treatment, and you may need to take multiple doses to get rid of the pinworms completely.
Prevention
Methods to help prevent the spread of pinworm eggs include:
- Wash in the morning. Because pinworms lay their eggs at night, washing the anal area in the morning can help reduce the number of pinworm eggs on your body. Showering may help avoid possible re-contamination in bath water.
- Launder in hot water. Wash bed sheets, night clothes, underwear and towels in hot water to help kill pinworm eggs.
- Don't scratch. Avoid scratching the anal area. Trim your child's fingernails so there's less space for eggs to collect. Discourage nail biting.
- Wash your hands. To reduce your risk of getting or spreading an infection, be sure to wash your hands thoroughly after a bowel movement and before eating.
- Parasites and Health: Enterobiasis. Centers for Disease Control and Prevention. http://www.dpd.cdc.gov/DPDx/html/Enterobiasis.htm. Accessed Dec. 4, 2009.
- Dent AE, et al. Enterobiasis. In: Kliegman RM, et al. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/174305878-6/925552497/1608/740.html#4-u1.0-B978-1-4160-2450-7..50293-0_6143. Accessed Dec. 4, 2009.
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- Ferri FF. Pinworms. In: Ferri's Clinical Advisor 2010. Philadelphia, Pa.: Mosby Elsevier; 2009. http://www.mdconsult.com/das/book/body/174689871-3/926963641/2088/500.html#4-u1.0-B978-0-323-05609-0..00025-3--sc0155_10293. Accessed Dec. 8, 2009.
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