Itchy Anus at Night: Pinworms or Not?

An itchy anus at night is the classic sign of pinworm, because female pinworms leave the intestine at night to lay eggs on the skin around the anus. It is not the only cause, though: hemorrhoids, irritation from soaps or wipes, diarrhea, yeast infections and other anal conditions can all cause itching, so the most useful next step is a simple test that shows whether pinworm is really the reason.

This page explains how to tell pinworm itching apart from other common causes, how pinworm is confirmed, and when to see a clinician in person. It is general education, not a diagnosis.

Why pinworm itching is worse at night

MedlinePlus describes pinworms as the most common worm infection in the United States. People swallow the microscopic eggs, usually after touching something contaminated and then touching their mouth. The worms grow in the intestine, and the females then move to the skin around the anus, especially at night, to lay more eggs. That is what causes the intense itching, and it is why the itching tends to wake people up or keep them from sleeping.

Scratching moves eggs onto the fingers and under the fingernails, where they can spread to bedding, towels, surfaces and other people in the home. Pinworm is most common in school-age children, so adults usually catch it from a child in the household. Our guide to pinworm treatment for adults covers how adults get it and what the whole household can do. For the risks of leaving it alone, see are pinworms dangerous if left untreated?

Pinworm or something else?

MedlinePlus lists many causes of anal itching besides parasites. This table compares the most common ones. It is a rough guide only; a clinician has to confirm the cause.

| Possible cause | What often points to it | Notes | |---|---|---| | Pinworm | Intense itching that is worst at night; someone else in the home, often a child, also itches; tiny white threads seen around the anus, on underwear or on toilet paper | Confirmed with a tape test | | Hemorrhoids | Itching with a tender lump near the anus, ache when sitting, or bright red blood after a bowel movement | NIDDK lists anal itching as a symptom of external hemorrhoids | | Anal fissure | Pain during bowel movements and blood on the stool or toilet paper | A small tear in the lining of the anus | | Irritation | Itching that started after a new soap, scented toilet paper or wipes, or a lot of wiping and scrubbing | Scents and dyes are a common trigger | | Diarrhea or certain foods | Itching after loose stools, or after spicy food, caffeine or alcohol | Keeping the skin clean and dry matters | | Yeast infection | Itching after a course of antibiotics, or itching with a red rash | Antibiotics can be a trigger | | Sexually transmitted infection | Itching with sores, discharge or a possible exposure | Needs testing in person |

Pinworms vs hemorrhoids

These two are the most commonly confused. With pinworm, the itching is the main symptom, it is usually worst at night, and other people in the home may have it too. Hemorrhoids are more likely to come with a lump, an ache when sitting, or bright red blood after a bowel movement, according to the NIDDK. Any bleeding from the rectum should be checked by a clinician, because the NIDDK notes it can also be a sign of other bowel conditions.

When it is not worms

If the itching is not worse at night, nobody else in the home is itchy, and a tape test is negative, a cause other than pinworm is more likely. MedlinePlus points to gentle cleaning, avoiding scented products, keeping the area dry and not scratching as the basics of self-care. A clinician can examine the area and suggest what fits your situation.

How pinworm is confirmed

Pinworm is usually confirmed with a tape test. MedlinePlus explains that a piece of clear tape is pressed against the skin around the anus first thing in the morning, before bathing or using the toilet, and a lab or clinician then looks at it under a microscope for eggs. MedlinePlus notes the test may need to be done on 3 separate days to improve the chances of finding eggs. The worms themselves are tiny, white and threadlike, and some people see them around the anus at night. See our step-by-step pinworm tape test guide.

An ordinary stool test is not the usual way to find pinworm, because the eggs are laid on the skin rather than passed in the stool. Our page on what to expect from a stool test for parasites explains when that test is used instead. If you saw a worm in the toilet or on toilet paper, see white worms in stool.

When to see a clinician in person

Get care in person rather than online if you:

• See blood from your rectum, or have black, tarry stools
• Have a lump, a rash, sores or discharge around the anus
• Have a fever, or severe or worsening pain
• Still itch after two to three weeks of self-care, which MedlinePlus says is a reason to contact your provider
• Are pregnant or breastfeeding, or the person itching is a child

Getting a prescription online

If a clinician has confirmed pinworm, or a household member has been diagnosed and you have the same symptoms, a licensed provider can review a written health assessment through Get It Prescribed and decide whether mebendazole is appropriate for you. Pinworm is one of the labeled uses for mebendazole. There is a one-time $50 consultation fee, and mebendazole costs $3.50 per capsule, with the quantity decided by the prescriber. The service is available in all 50 states and the District of Columbia, and some states require a live phone or video visit. How it works shows each step. A prescription is never guaranteed, and the service is for adults only.

The mebendazole dispensed through Get It Prescribed is a compounded preparation made by a licensed compounding pharmacy for an individual patient. Compounded preparations are not FDA-approved, and the FDA does not review them for safety, effectiveness or quality. They are not generics of, or substitutes for, the brand-name product.

Related questions

Why is my anus itchy only at night?

Itching that is worst at night is the classic sign of pinworm, because female pinworms move to the skin around the anus at night to lay eggs. Other causes, such as hemorrhoids or irritation from soaps and wipes, can also itch at night, so a tape test is the best way to find out.

Can you have an itchy anus at night without worms?

Yes. MedlinePlus lists many other causes, including hemorrhoids, scents or dyes in soap or toilet paper, diarrhea, spicy food, caffeine or alcohol, antibiotics, yeast infections and sexually transmitted infections. A negative tape test and no itching in the rest of the household make pinworm less likely.

How can I tell pinworms from hemorrhoids?

Pinworm mainly causes itching that is worst at night and often affects more than one person in the home. Hemorrhoids are more likely to cause a tender lump, an ache when sitting, or bright red blood after a bowel movement. Bleeding should always be checked by a clinician.

How do I check for pinworms at home?

Ask your clinician for a tape test kit. Clear tape is pressed against the skin around the anus first thing in the morning, before bathing or using the toilet, and the tape is then checked for eggs under a microscope, sometimes on 3 separate mornings. Some people also see the tiny white worms around the anus at night.

Should everyone in my house be checked for pinworms?

Pinworm spreads easily through eggs on hands, bedding and surfaces, so MedlinePlus notes that more than one household member is often infected and the whole household is often treated. Ask your clinician whether others in your home should be checked.

Sources

• MedlinePlus: Anal itching - self-care — causes of anal itching, self-care, and when to contact a provider.
• MedlinePlus: Pinworms — how pinworm spreads, why the itching happens at night, the tape test and household care.
• MedlinePlus: Pinworm test — how the tape test is done.
• CDC: About Pinworm Infection — pinworm symptoms, spread and diagnosis.
• NIDDK: Symptoms and Causes of Hemorrhoids — symptoms of external and internal hemorrhoids, and why rectal bleeding needs checking.
• MedlinePlus: Anal fissure — symptoms of a small tear in the anal lining.
• MedlinePlus: Anal Disorders — overview of common anal conditions and their symptoms.
• DailyMed: mebendazole chewable tablet prescribing information — labeled uses, including pinworm.
• FDA: Compounding and the FDA — Questions and Answers — what compounded preparations are and how they are regulated.