Treating Pinworms

The pinworm, or Enterobius vermicularis, is one of the most common parasitic infections of humans. Treating pinworms can usually be done in one dose of ...

Question

I have 3 children. In the last 2 years the same child has been infected with pinworms 3 times. We belong to a family medicine group. The first doctor elected to treat the whole family, but the 2nd and 3rd time I had to request this from different doctors. My question is, does the medicine to treat this infection hurt the family members who are not suffering from this gross infestation? Also, could the worms or eggs live dormant in my daughter or could she be a carrier? Or is there such a thing as a carrier?
Centreville, Virginia

Dr. Greene's Answer

When I was a young boy, I used to have a creepy-crawler set. I delighted in making these little jiggling critters. I found particular joy in trying to make other people shudder when they saw the various worms and bugs that I had created. Although we adults often shudder at pinworm infections, most kids don’t have this same gut response.

What Are Pinworms?

The pinworm, or Enterobius vermicularis, is one of the most common parasitic infections of humans. Somewhere between 10% and 40% of children have pinworms at any given time (Pediatric Consult, Williams and Wilkins 1997). The infections are usually limited to children below the age of twelve.

The adult pinworms are white and measure less than one-half inch long, with the diameter of a strand of thread. These tiny roundworms are quite complex. Like us, they have mouths, throats, and gastrointestinal tracts. Like us, they have nervous systems. The females have a vagina, a uterus, and ovaries. The males have a testicle, vas deferens, seminal vesicle, and ejaculatory duct. They eat, drink, pee, poop, and reproduce sexually.

The adult worms live in the colons (large intestines) of human children and apparently feed on human fecal matter.

When an adult male and female worm copulate, each female pinworm produces about 10,000 fertilized eggs. At night, the pregnant female migrates from the colon, out through the child’s anus and onto the skin of the buttocks. There she violently expels all of her eggs and then dies. Some of the eggs become airborne and land elsewhere in the child’s room, but the great majority of the fertilized eggs stay on the skin of the child’s buttocks. The eggs mature within six hours of being laid.

The adult worms and the eggs on the skin of the buttocks can cause intense itching in the child. When the sleeping child scratches, the eggs often get on the fingers and under the fingernails. If the child then sucks his or her thumb or otherwise brings his or her hand to the mouth (perhaps while eating breakfast), the pinworm eggs are swallowed. Usually, they hatch within the small intestine and mature there. When they become adults they move to the colon where they take up residence. The entire life cycle lasts four to six weeks.

Occasionally the story goes a little differently. Sometimes a child can inhale airborne eggs and become infected that way. Every now and then the eggs will hatch on the skin of the buttocks, and the immature larvae will crawl back through the anus, up into the rectum and eventually arrive in the colon. Also, the eggs can hatch on the skin of girls and the larvae crawl into the vagina instead of the rectum. This happens in up to 20% of girls with pinworms (Nelson’s Textbook of Pediatrics, Saunders 1996). The vaginal pinworms usually die out with no outside help.

Pinworm Symptoms

Most children with pinworms have no symptoms at all. In the same way that many bacteria live in our intestines without making us sick, pinworms can live happily in our intestines without causing any problems (Parasitic Diseases, Springer-Verlag 1982). Since the pinworm almost always stays in the gastrointestinal tract (or vagina), there is usually no systemic illness.

Some children, however, develop nighttime itching of the skin around the anus. For a small number of these children, the itching can be quite intense. The girls who develop vaginal pinworm infections often develop vaginal itching and sometimes a vaginal discharge. However, attempts to link pinworm infection to bed wetting or grinding of the teeth have been unsuccessful.

Stool and blood tests are not very helpful in diagnosing pinworms. Seeing a worm clinches the diagnosis. Check your child’s skin with a flashlight during the night and first thing in the morning. Look for white, wiggling threads. If it’s not wiggling, it’s probably just lint. Occasionally a wiggling worm will be seen on the surface of a stool. Pinworms are so common that children with nighttime anal itching are often treated without any lab test at all. The classic diagnostic tool is to apply a piece of transparent tape to the skin near the anus first thing in the morning. This tape can then be attached to a glass slide and examined under a microscope for the presence of eggs. Your doctor can supply you with a pinworm lab kit, if necessary.

Treating Pinworms

Treatment is with a single dose of an anti-pinworm drug such as albendazole (Albenza), or pyrantel pamoate (the active ingredient found in Reese’s Pinworm Medicine, which is available over the counter). Most children and adults experience no side effects (use of these drugs in children less than two years old is limited). Hives or other allergic rashes have been reported only rarely. Very rare cases of convulsions have occurred.

This medicine kills the worms 95% of the time but does not kill the eggs. Hence, retreatment in two weeks is a good idea. Doing this is almost 100% effective at eradicating the pinworms. Girls with vaginal itching alone do not necessarily need treatment since the problem will often disappear on its own.

Physicians disagree about whether or not to treat all family members. Often treating the infected child alone will get rid of the infestation. Anyone who sleeps with the child, or any family member or friend with itching should be treated. In stubborn cases, it’s a good idea to treat all family members regardless of symptoms.

It is certainly possible that your daughter is an asymptomatic carrier. In any case, reinfections with pinworms are quite common.

There are no differences in pinworm infections on the basis of race or socioeconomic class. Neither is pinworm infection evidence of poor hygiene. This is a very easily transmissible infection that is very common in children. It is easily spread at home, school, or daycare (pets, though, have no part in the pinworm story). Since most kids experience no ill effects whatsoever, extreme measures to treat pinworms are not wise.

I usually recommend trimming the fingernails, scrubbing the hands (after awakening, before meals, and after toileting) and machine washing the bedding on the treatment day. These hygiene measures have never been proven to help at all, but they still seem like a good idea to me.

Although pinworms are like creepy-crawler bugs in that they are usually harmless (and seem worse than they are!), they are still a real nuisance! I hope you and your family will soon find relief from this bothersome problem.

Last medical review on: May 12, 2018
About the Author
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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We have been having trouble with recurring pinworm infections for years. I never had them at all until my late 30’s, when I suddenly realized all three of my children had pinworms. They had probably had them at least a year before I caught on that the itchy bottoms at night were pinworm. I finally saw the worms. After that, it’s been a continual cycle of 4-6 months of having to retreat. We have moved three times over the years, and the infections always come back. We are pretty clean people, I am not a bleach fanatic but I keep my house pretty clean!
Lately my symptoms recurred. I took a Reese’s treatment but this time, instead of the normal relief I have the next night, I still had very distinct wriggling sensations (you know it when you’ve had it). Is it ok to retreat 2 nights in a row? I am wondering if I didn’t shake the bottle well enough or get enough of the active ingredient
I also just saw that my cat has worms this morning. As I am aware that pinworms are species-specific, I wonder if I have caught something different from my cat, and if Reese’s would even be effective for that.
This worm ordeal is so so tiring. I know people who have treated it and never had it return, but the story is very different for me and my family :(
We have even all taken the $900 medicine which, thankfully, our insurance mostly paid for. But IT STILL CAME BACK

Hi Cameron,

Thanks for writing in. That took courage. Sadly, pinworms tend to be embarrassing, but they really should not be. Certainly, your doctor will not be embarrassed to talk about them and to help you get treatment.

Regarding guilt — as a child and even as a young teen, you didn’t know that they were contagious. You do not need to feel any guilt for not informing folks. But now that you know, you need to take action to protect yourself and others.

As Dr. Greene says, “Anyone who sleeps with the child, or any family member or friend with itching should be treated. In stubborn cases, it’s a good idea to treat all family members regardless of symptoms.” That means you do not need to discuss this with friends or family members unless you have slept with them. Of course, if you have a romantic relationship, and if you have been physically close, that person will be at risk … and could pass them back to you after you are cured.

All sheets and linens need to be washed at the time of treatment, but they aren’t like lice that require the whole house to be cleaned.

As for your last question, I do not think anyone will vomit when you discuss this. Likely your parents will say how sorry you are that you’re going through this and help you get treatment right away. Of course, I don’t know your parents, but most adults understand that things like pinworms are part of life and you just need to deal with them.

I hope that helps.
Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

I figured out I had pinworms a couple years ago I’d guess, and my hypothesis is that I’ve had them since I was I kid and just never had it treated (for reference, I’m almost 17). Is that possible? Anyway, I figured I would just live with it since it wasn’t causing me too many problems and is pretty harmless. Maybe I’d get it checked out later in life. However, recently I’ve done more research and found out how contagious they are, so I have a few questions.

1: How do I deal with the guilt that comes along with not bringing this up earlier? I’ve been really in my head about this and have been feeling incredibly guilty for putting my family and possibly my friends at risk when I could have just brought it up when I noticed the infection, or literally any time afterwards. I was and still am extremely embarrassed about this.

2: Will I need to inform close contacts outside my household? Close family friends and such.

3: How difficult is it to clean the house for treatment, and when should the cleaning start? I can’t seem to wrap my head around the cleaning process and I’m worried about adding stress to my family’s life, especially right after the holidays.

4: This last question is pretty specific to me; I have a pretty bad fear of vomit, and it’s causing my to worry that my parents will be so disgusted that they will throw up. If this isn’t a question you can answer that’s fine, but how would people usually react to this? Would it really be that intense? I doubt it, but I’m still freaked out.

Thanks for your time if you can get around to this one.

Hi Cameron,

Thanks for writing in. That took courage. Sadly, pinworms tend to be embarrassing, but they really should not be. Certainly, your doctor will not be embarrassed to talk about them and to help you get treatment.

Regarding guilt — as a child and even as a young teen, you didn’t know that they were contagious. You do not need to feel any guilt for not informing folks. But now that you know, you need to take action to protect yourself and others.

As Dr. Greene says, “Anyone who sleeps with the child, or any family member or friend with itching should be treated. In stubborn cases, it’s a good idea to treat all family members regardless of symptoms.” That means you do not need to discuss this with friends or family members unless you have slept with them. Of course, if you have a romantic relationship, and if you have been physically close, that person will be at risk … and could pass them back to you after you are cured.

All sheets and linens need to be washed at the time of treatment, but they aren’t like lice that require the whole house to be cleaned.

As for your last question, I do not think anyone will vomit when you discuss this. Likely your parents will say how sorry you are that you’re going through this and help you get treatment right away. Of course, I don’t know your parents, but most adults understand that things like pinworms are part of life and you just need to deal with them.

I hope that helps.
Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

Hi Britany,

What an ordeal. So sorry you’re going through this — especially now.

During COVID most doctors are doing as much as they can via phone or Zoom. Your doctor will have your specific history and know how you tend to react to medicines so it’s best you give them a call.

Hopefully, this will all be behind you soon.

I hope that helps.
Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

Hi. I don’t know how long we’ve been dealing with pin worms. The symptoms started to intensify in the past 3 weeks before I finally spotted one on my child’s poop. That was on nov 6th, we treated that night that combantrin. I’ve been following all the cleaning and hygiene measures religiously. We treated for a second time last Saturday November 21st. It is now nov 29th a week since our last treatment. My husband did pass some dead worms.. he showed no symptoms throughout this entire pinworm ordeal. My two children’s symptoms have vanished since treating, ive also been checking them during the night and haven’t seen any worms. I’m still itchy though but especially during the day. I’m not extremely itchy but still slightly irritated. Should I treat again or seek recommendations from a doctor? I’m really trying to avoid the doctors office because of this whole covid pandemic. Please help me . 😢😢

Hi Britany,

What an ordeal. So sorry you’re going through this — especially now.

During COVID most doctors are doing as much as they can via phone or Zoom. Your doctor will have your specific history and know how you tend to react to medicines so it’s best you give them a call.

Hopefully, this will all be behind you soon.

I hope that helps.
Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

Ok this i know is gonna sound crazy!!!!!! But WE’VE BEEN FIGHTING THRM 10YRS!!Only 1 person. They go and come back. We have new house new everything???? Can’t figure this out!!! Oh and she’s almost an adult!!! Someone please HELP

Thanks for sharing! You are doing amazing work! Love this website ❤️. My parasite infection began with extreme fatigue. I also noticed that my belly was pretty swollen. I felt like a bus had hit me, and my appetitive had come to a complete halt. So happy 😊 I found “Noworm365” in Google and got the treatment (vermox-mebendazole). Decreased appetite was a red flag for me because I am always hungry.

Mi,

I’m so sorry you are going through this.

If you see little worms all over your body, this may not be pinworms. Pinworms live in the digestive system, not on the skin. Before you try other treatments, you may need to be checked by a doctor for a definitive diagnosis.

I hope that helps.
Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

I think i have some pinworms. I purchased 3 tablets of abendazol but i cant find more of it. I took 1 tablet yestarday. The headache stoped. Iss there someething else that can kill those worms and eggs? On mang pages they say pumpki. Seeds help but they only sell them baked and the pharm toldd me they dont help. I see little worms all over my body. Its so bad.

Mi,

I’m so sorry you are going through this.

If you see little worms all over your body, this may not be pinworms. Pinworms live in the digestive system, not on the skin. Before you try other treatments, you may need to be checked by a doctor for a definitive diagnosis.

I hope that helps.
Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.

Bill,

That sounds traumatic at best. What an ordeal.

I’d say it’s time to see a doctor and we’d love to know what they have to say. So interesting!

Best, @MsGreene
Note: I am the co-founder of DrGreene.com, but I am not Dr. Greene and I am not a doctor. Please keep that in mind when reading my comments and replies.