Topic Overview
What are pinworms?
Pinworms are a type of
parasite that lives in the
digestive system of humans. They are common throughout the world, especially in
school-age children.
Adult pinworms look like small, white threads
that are no more than
0.5 in. (12.7 mm) long. You
need a microscope to see the eggs.
What causes pinworms?
Pinworm infections are spread from human to human. Pets don't get pinworms and can't spread them to humans. Most people get pinworms by swallowing the worms'
eggs. This happens when someone with pinworms scratches around the
anus, gets eggs on his or her hands (or under the
fingernails), and touches you or a surface that you later touch. When eggs get
on your hands or food and then you eat, the eggs go into your mouth. And they
move into your stomach and then to your rectal area.
The eggs
turn into worms in about a month. A pinworm crawls out of the body during the
night and lays eggs on the skin around the anus. The wiggling motion when the
worm lays eggs may irritate the skin and cause itching.
Pinworms
spread easily in families, day care centers, schools, camps, and other places
where groups of people live. If one person in your family has pinworms, others
probably do too. Pinworm infections can happen to anyone. They are not related
to being unclean.
What are the symptoms?
The most common sign of pinworms is itching
around the anus. Many people with pinworm infections have no symptoms and may
never be aware of the infection. In rare cases, itching becomes severe and may
cause restless sleep, loss of appetite, and
anxiety.
Pinworms don't usually cause
serious health problems, and they do not carry disease. But it is possible to
get a skin infection from scratching around the anus.
The
incubation period—the time from first contact with eggs until symptoms
appear—is usually 1 to 2 months or longer.
How are pinworms diagnosed?
Your doctor can find out if you have a pinworm
infection by asking about your past health and checking the skin around your
anus. He or she may ask you to collect a sample from around the anus by using a
piece of clear, sticky tape. This piece of tape will be put under a microscope
to look for pinworm eggs.
How are they treated?
You can treat pinworm infections with
over-the-counter and prescription medicines. These
medicines can help keep you from getting infected again and from spreading
pinworms to other people.
How do you keep from spreading pinworms or getting them again?
To limit the
chances of getting pinworms or of spreading them to others:
- Wash your hands carefully and often.
- Avoid scratching around your anus.
- Keep your
fingernails short.
- Wash clothes and bedding regularly.
- Bathe and change your underwear every day.
- Avoid sharing a bathtub, sharing washcloths, or reusing washcloths.
If family members get pinworms again, all family members
may need to take medicine to kill pinworms.
Frequently Asked Questions
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Learning about pinworms:
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Being diagnosed:
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Getting treatment:
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Cause
Pinworm
infections are usually caused by swallowing the eggs of the pinworm (Enterobius vermicularis) after coming in contact with an
infected person or with an object that has eggs on its surface. Infection can
also be spread when a person inhales airborne eggs, but this is rare. It's also rare for pinworms to spread to people in a swimming pool.
In some cases, pinworm infection persists because eggs hatch outside the anus and the
young worms crawl back inside the body.
Symptoms
Pinworms do not
usually cause any symptoms beyond minor itching around the
anus. Many people with pinworm infections have no
symptoms and may never be aware of the infection.
The most common symptoms of pinworm infection
in children include:
- Itching around the anus. For most children this
symptom is mild. Only in rare cases do children have very severe
itching.
- Restless sleep (itching is often worse at night).
Other possible symptoms that may be present but are much
less common include:
- Itching in the
genital area.
- Pain or burning when urinating.
- Worms in
stool (rarely seen).
- Abdominal pain (rare, except when
complications develop).
The above symptoms may result in
anxiety.
What Happens
The time it takes from when
the eggs first enter your body to the time that an adult female pinworm lays
new eggs is about one month. The eggs of
pinworms get into the body through the mouth and
develop into worms in the lower
digestive system. They begin growing in the small
intestine and move into the large intestine, where
they become adult worms. The worms live by eating nutrients found in your
digested food.
Female pinworms crawl out of the body and lay their
eggs during the night on the skin around the
anus. The female worm's wiggling motion when laying
eggs is believed to irritate the skin and cause itching. The eggs have a damp,
sticky covering, so when children scratch the skin around the anus, eggs stick
to their fingers and get stuck under their fingernails. The eggs can then be
transferred into their mouths or onto objects such as faucets and food. The
eggs can also stick to clothing, bedding, and furniture. The eggs can live 2 to 3 weeks outside the body.
How pinworms are spread
Pinworms are spread when
someone with pinworms scratches around the anus, gets eggs on his or her hands
(or under the fingernails), and touches another person or an object. Infection
can occur when:
- An uninfected person puts a hand in his or her mouth
after being touched by an infected person.
- An uninfected person
touches a pet or an object (such as bedding, clothes, dishes, or toys) that
carries pinworm eggs and then puts a hand in his or her
mouth.
- Bedding or clothes of a person who has pinworms are fanned
in the air. Eggs can float through the air and be swallowed by other
people.
A person with pinworms can be reinfected by any of the
means listed above or when eggs hatch on the skin around the anus and the young
worms (larvae) crawl back into the body.
Pinworm infection is
contagious as long as living pinworm eggs are spread to and swallowed by
someone. Because the medicine to treat pinworm infection kills adult worms but
not pinworm eggs, a person who has received one treatment for pinworms can
still spread the infection. This is why it is important to
wash your hands often when you know that someone is infected. A second
treatment with medicine is usually needed about 2 weeks after the initial treatment to
kill any worms that have hatched during that time.
Complications
Complications from
pinworms are rare. The most frequent complications are bacterial infection
around the anus or of the skin in the genital area. This is usually because of
skin irritation or scratches from itching in these areas.
What Increases Your Risk
Factors that increase the
risk of being infected by
pinworms include:
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Age. Pinworm infections are most common in
preschool and school-age children.
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Household contact. If one child in a home gets a
pinworm infection, it is likely that other children in the home will have the
infection. Parents are also more likely to get the infection.
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Attending day care centers, schools, and summer camps. Pinworms are easily transmitted and spread among groups of
children.
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Living in an institution. Up to half of people
living in an institution may be infected by pinworms.1
Factors that increase the risk of spreading pinworm
infections include:
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Living in an institution. Pinworms are easily
transmitted and spread where people are living in close conditions (such as
institutions).
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Poor hygiene practices, especially poor hand-washing. An infected person can spread pinworms to others if
he or she does not wash his or her hands well.
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Sharing bedding. Also, fanning the bedding of an
infected person can release pinworm eggs into the air.
When To Call a Doctor
Call your doctor if:
- You or your child has symptoms of
pinworm infection, and no one in your household has had the infection before.
- You see pinworms on your child
(when bathing the anal area or wiping his or her bottom) or on your child's
bedding or clothes.
- You or your child has symptoms, you have not seen any worms, and
you want to see the doctor even though you or your child has had the infection before.
- You have started over-the-counter medicine to
treat the pinworms, and the infection has not cleared up. (Do not use an
over-the-counter medicine for pinworms in a child younger than 2 without first
talking to a doctor.)
- You have had a pinworm infection recently and
now have symptoms of reinfection.
- Your doctor prescribed medicine for pinworms, and the
infection has not cleared up within the expected time frame (usually within 4
to 6 weeks).
- You or your child is having side effects from medicine
for pinworm infection.
- You or your child with a pinworm infection
develops other symptoms.
- Fever or abdominal pain may be a sign of
complications of pinworm infection.
- Redness, tenderness, or
swelling in the genital area may be a sign of skin
infection.
- Itching in the genital area or vagina may be a sign of
vaginal pinworm infection.
- Pain when urinating, frequent or urgent
urination, or lack of control of urination may be a sign of pinworm infection of
the
urinary tract.
Watchful waiting
Watchful waiting
is not appropriate
when a person has symptoms of a pinworm infection. Although pinworm infections
are usually mild and do not cause any serious health problems, treatment should
be considered because it helps stop the spread of the infection to others and
helps prevent reinfection.
Watchful waiting may not be appropriate
for family members of a person infected with pinworms. If one member of a
family has a pinworm infection, it is very likely that other members also are
infected. This is very important if a family member is pregnant. A pregnant
woman may not be able to take pinworm medicine, and treating all other members
of the household may decrease the likelihood of her getting the infection. Some
doctors recommend treating all members of the family to help prevent
reinfection and the spread of infection.
Who to see
Health professionals who can diagnose and treat pinworm
infections include:
If
complications of pinworm infection develop, you may
need to see a specialist who deals with conditions affecting the body system
involved, such as:
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Exams and Tests
When
pinworm infection is suspected, the doctor will ask about your or your child's medical history and do a physical exam. During
the physical exam, your doctor will examine the skin around the
anus for redness and irritation. Also your doctor may
ask you to collect a sample by using a piece of transparent adhesive tape. This
test, sometimes called a
cellophane or "Scotch tape" test, involves pressing a
piece of transparent tape on the skin around the anus in the morning
before you or your child gets up or bathes. This piece of tape is then viewed
under a microscope to look for pinworms and their eggs. The doctor may ask you to repeat the test a few times.
Other tests may be done if the physical exam and
cellophane test have not shown pinworms and an infection is still
suspected.
- Stool sample. Although collecting a stool
sample may be useful, it is usually not the best way to diagnose pinworms since
female pinworms do not lay many eggs in the rectum.
- Examination of
the lower intestine (colonoscopy).
This test is done in only very rare cases of pinworms that have not cleared up
with treatment or in cases where the diagnosis is unclear.
If a
complication of pinworm infection is suspected, more
tests may be done. The specific tests that are needed will depend on the
person's symptoms and the part of the body that is affected.
Treatment Overview
Pinworms can be
successfully treated with:
- Medicine. Over-the-counter and prescription medicines come in liquid, chewable tablet, and pill forms. Women who are pregnant or
breast-feeding and children younger than 2 should not take over-the-counter
medicine without first talking to a doctor about the risks and benefits of the
medicine.
- Steps to prevent reinfection and the spread of infection,
including frequent
hand-washing and routine washing of clothes and
bedding. These measures are important and helpful even if medicine is not being
used.
Pinworms are treated with medicine when:
- Signs and symptoms of pinworm infection are
present, such as itching around the
anus.
- Pinworm infection of family members
and other close contacts is likely.
If severe itching is present, your doctor may prescribe a
soothing cream to be applied to the anal area. If complications of pinworm
infection develop, additional treatments may be needed.
What to think about
Some doctors suggest treating
all close contacts of a person with pinworms even if there are no symptoms.
Treating contacts with over-the-counter medicine can help prevent reinfection
and the spread of pinworms to other people. This is especially important in
households where pinworm infections come and go.
Treatment of all
household members may be recommended if someone in the household is pregnant,
breast-feeding, or younger than 2. These people may not be able to take pinworm
medicine, and their chance of infection may be lower if all other members of
the household are treated.
Many doctors suggest a second treatment 2 weeks after the first treatment to kill
any adult worms that may have hatched from eggs during that time. Pinworm
medicine does not kill pinworm eggs.
Prevention
Hand-washing is the best way to help prevent pinworm infections. For more information about how to prevent reinfection and the spread of infection to other members of the household, see the Home Treatment
section of this topic.
Home Treatment
For people with
pinworm infections, home treatment is very important
to prevent reinfection and the spread of infection to other members of the
household. Good home treatment includes the following measures:
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Wash hands carefully and often. Frequent
hand-washing by all family members, especially before
eating or preparing food and after using the toilet, is very important in
preventing the spread of infection. Hand-washing will help remove eggs that may
have stuck to the hands. Scrubbing your hands and fingernails for 1 minute is
recommended.
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Control scratching. Itching around the
anus caused by a pinworm infection usually occurs at
night. Wearing gloves may help prevent scratching.
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Keep fingernails short. Pinworm eggs can get under
the fingernails when the person with a pinworm infection scratches. Cutting the
nails short may help prevent eggs from sticking under the nails. Discourage
thumb-sucking if your child has a pinworm infection.
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Wash clothes and bedding. Washing underwear,
pajamas, and bedding each morning and drying them in a heated dryer may help prevent reinfection.
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Bathe carefully and every day. Make sure the skin
around the anus is cleaned when bathing. This will remove pinworm eggs. Bathing
in the morning may help get rid of a lot of the eggs. Showers may work better
than baths because there is less chance of getting water that contains pinworm
eggs into your mouth.
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Do not fan the bedding of an infected person. Fanning the sheets and blankets of an infected person can
put pinworm eggs into the air. Airborne eggs can be swallowed when you breathe
through your mouth.
Preventing the spread of infection is
especially important in households that include children younger than 2 or
pregnant women, because they may not be able to take medicine for
pinworms.
Medications
Medicine is often used for
pinworm infections that are causing symptoms such as
itching. Over-the-counter and prescription medicines come in liquid, chewable tablet, and pill forms. Most pinworm
infections are cured with medicine.
Because medicines do not kill
pinworm eggs, two doses are usually needed, 2 weeks apart. The second dose is
necessary to kill any worms that may have hatched from eggs after the initial
treatment. In some cases of reinfection, 4 to 6 treatments (spaced 2 weeks
apart) are needed.
Medication Choices
Prescription medicines
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Albendazole and mebendazole
Nonprescription medicine
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Pyrantel pamoate (such as Pin-X or Reese's Pinworm Medicine)
Do not use other medicines to treat pinworms without
first speaking to your doctor.
What to think about
Pinworm medicine is not
recommended for use by pregnant women, breast-feeding women, or children
younger than 2 without talking to a doctor about the risks and benefits of
medicine. These groups are advised to use measures to prevent reinfection
rather than using medicine. For more information, see the Home Treatment
section of this topic.
Other Places To Get Help
Organizations
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American Academy of Pediatrics
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| 141 Northwest Point Boulevard |
| Elk Grove Village, IL 60007-1098 |
| Phone: |
(847) 434-4000 |
| Fax: |
(847) 434-8000 |
| Web Address: |
www.aap.org |
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The American Academy of Pediatrics (AAP) offers a
variety of educational materials about parenting,
general growth and development, immunizations, safety, disease prevention, and more. AAP guidelines for various conditions and links to other
organizations are also available.
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Centers for Disease Control and Prevention (CDC):
Parasites
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| 1600 Clifton Road |
| Atlanta, GA 30333 |
| Phone: |
1-800-CDC-INFO (1-800-232-4636) |
| TDD: |
1-888-232-6348 |
| Email: |
cdcinfo@cdc.gov |
| Web Address: |
www.cdc.gov/parasites |
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The
U.S. Centers for Disease Control and Prevention (CDC)'s website on parasites offers information on diseases caused by parasites. It provides information on topics such as malaria, neglected tropical diseases, and parasitic infections in the United States. There are also links to related information, such as a glossary and a site on healthy water, and other references and resources, such as statistics on parasitic diseases.
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KidsHealth for Parents, Children, and
Teens
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Nemours Home Office
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| 10140 Centurion Parkway |
| Jacksonville, FL 32256 |
| Phone: |
(904) 697-4100 |
| Web Address: |
www.kidshealth.org |
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This website is sponsored by the Nemours Foundation. It
has a wide range of information about children's health—from allergies and
diseases to normal growth and development (birth to adolescence). This website
offers separate areas for kids, teens, and parents, each providing
age-appropriate information that the child or parent can understand. You can
sign up to get weekly emails about your area of interest.
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National Institute of Allergy and Infectious Diseases
(NIAID), National Institutes of Health
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| NIAID Office of Communications and Government Relations |
| 6610 Rockledge Drive, MSC 6612 |
| Bethesda, MD 20892-6612 |
| Phone: |
1-866-284-4107 toll-free |
| Phone: |
(301) 496-5717 |
| Fax: |
(301) 402-3573 |
| TDD: |
1-800-877-8339 |
| Web Address: |
www.niaid.nih.gov |
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The National Institute of Allergy and Infectious
Diseases conducts research and provides consumer information on infectious and
immune-system-related diseases.
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References
Citations
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American Academy of Pediatrics (2009). Pinworm infection (Enterobius vermicularis). In LK Pickering et al., eds., Red Book: 2009 Report of the Committee on Infectious Diseases, 28th ed., pp. 519–520. Elk Grove Village, IL: American Academy of Pediatrics.
Other Works Consulted
- Drugs for parasitic infections (2010). Treatment Guidelines From The Medical Letter, 8(Suppl): e1–e20.
- Hotez PJ (2009). Parasitic nematode infections. In RD Feigin et al., eds., Feigin and Cherry's Textbook of Pediatric Infectious Diseases, 6th ed., vol. 2, pp. 2981–2996. Philadelphia: Saunders Elsevier.
- Van Voorhis WC (2010). Helminthic infections. In EG Nabel, ed., ACP Medicine, section 7, chap. 35. Hamilton, ON: BC Decker.
Credits
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By
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Healthwise Staff |
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Primary Medical Reviewer
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John Pope, MD - Pediatrics |
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Specialist Medical Reviewer
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Susan C. Kim, MD - Pediatrics |
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Last Revised
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August 30, 2012 |