Intestinal Worms in Adults: Signs & Care

Intestinal worms in adults are parasites that live in the gut, and the ones adults in the United States are most likely to meet are pinworm, roundworm, hookworm, whipworm and Strongyloides. Many adults with a light infection have no symptoms, while others notice anal itching, belly pain, diarrhea or tiredness from anemia, and a clinician confirms which worm it is with a test before choosing a prescription medicine.

This page is a starting point. It explains how adults pick up each worm, the signs that can point to one or another, and why testing comes before treatment. Each worm has its own page, linked below, with the full detail. Ringworm is not on this list because it is a fungal skin infection, not a worm; see is ringworm a worm?

Which intestinal worms do adults get?

| Worm | How adults usually catch it | Signs that can point to it | Read more | |---|---|---|---| | Pinworm (Enterobius vermicularis) | Swallowing eggs from fingers, bedding or household surfaces, often from a child in the home | Itching around the anus, worse at night | Pinworm treatment for adults | | Roundworm (Ascaris lumbricoides) | Swallowing eggs from soil, food or water contaminated with human stool | Often none; belly pain, or a worm passed in the stool | Roundworm in humans | | Hookworm | Larvae in contaminated soil entering through bare skin | Itchy rash where larvae entered, belly pain, anemia | Hookworm in humans | | Whipworm (Trichuris trichiura) | Swallowing eggs from contaminated soil, food or water | Often none; heavy infections cause diarrhea with mucus or blood | Whipworm in humans | | Strongyloides stercoralis | Larvae in contaminated soil entering through bare skin | Often none; rash, belly pain, diarrhea, cough | Strongyloidiasis symptoms and treatment |

The CDC calls pinworm the most common worm infection in the United States. It can spread in any setting and often affects several people in one household. Roundworm, hookworm and whipworm are known as soil-transmitted worms, and the CDC says they occur mainly in warm, moist areas where sanitation is poor. In the United States they are uncommon, and an adult's risk is mostly tied to living in, or traveling to, places where they are common. Strongyloides also spreads through soil and can stay in the body for many years.

Symptoms of intestinal worms in adults

The CDC notes that people with only a few soil-transmitted worms usually have no symptoms, and that pinworm symptoms are usually mild. When adults do notice something, it is often one of these:

• Itching around the anus, especially at night, and poor sleep (typical of pinworm)
• Belly pain, bloating, nausea or loss of appetite
• Diarrhea, sometimes with mucus or blood
• Tiredness, weakness or pale skin from iron-deficiency anemia, seen with heavy hookworm or whipworm infections
• An itchy rash where larvae entered the skin, often on the feet (hookworm, Strongyloides)
• A cough or wheeze while larvae pass through the lungs (roundworm, hookworm, Strongyloides)
• A worm seen in the stool or around the anus (see what white worms in stool can mean)

None of these signs is specific to worms. Food poisoning, irritable bowel syndrome, other infections and many other conditions cause the same complaints, which is why a test matters more than a symptom checklist.

When to see a clinician in person

Get prompt, in-person care if you have:

• Blood in your stool, or black, tarry stools
• Severe or worsening belly pain, repeated vomiting or a swollen belly
• Signs of dehydration, fainting or a high fever
• Marked tiredness, shortness of breath or a racing heart, which can be signs of anemia
• A weakened immune system, or you take steroids or other immune-suppressing medicines. The CDC warns that Strongyloides can become a severe, body-wide infection in people with weakened immunity
• A pregnancy, or you are breastfeeding

How adults catch intestinal worms

Two routes cover almost every case.

Swallowing eggs. Pinworm eggs are carried on fingers, bedding, clothing and household items, and the CDC notes they can survive on objects for two to three weeks if not washed or cleaned. Roundworm and whipworm eggs come from soil, food or water contaminated with human stool, for example raw produce that was not washed, peeled or cooked.

Bare skin on contaminated soil. Hookworm and Strongyloides larvae live in soil contaminated with human stool and get in through the skin, most often the feet. The CDC says hookworm spreads mainly by walking barefoot on contaminated soil.

Pinworm passes easily from person to person within a home. Roundworm, whipworm and hookworm do not spread directly between people, because their eggs or larvae need time in soil first.

How intestinal worms are diagnosed

The test depends on which worm a clinician suspects:

• Pinworm: a tape test. MedlinePlus describes pressing the sticky side of clear tape to the skin around the anus in the morning, before bathing, so a clinician can look for eggs. It may need to be repeated on three separate days.
• Roundworm, hookworm and whipworm: a stool ova and parasite (O&P) test, in which a lab looks for eggs under a microscope. MedlinePlus notes that several samples over a few days may be needed, because parasites may not show up in every sample.
• Strongyloides: the CDC notes that ordinary stool exams often miss it, so a clinician may ask for several samples, use specialized stool methods or order a blood antibody test.

A blood count may also show anemia, or raised eosinophils, a type of white blood cell that often goes up with worm infections. Our guide to the stool test for parasites explains how the O&P test works and what the results mean.

How intestinal worms in adults are treated

Treatment is a prescription decision made after the worm is identified, and the medicine depends on which worm it is.

• Pinworm, roundworm, hookworm and whipworm are the four labeled uses listed in the prescribing information for the brand-name mebendazole chewable tablet. MedlinePlus also names albendazole among the medicines clinicians use for some of these worms. For pinworm only, an over-the-counter medicine, pyrantel pamoate, is sold in US pharmacies; see pinworm medicine: OTC or prescription?
• Intestinal strongyloidiasis is one of the two labeled uses in the prescribing information for the brand-name ivermectin tablet. The other is onchocerciasis (river blindness), a skin and eye infection rather than an intestinal worm.
• Tapeworms and flukes are different kinds of parasite. They are not covered by mebendazole's or ivermectin's labeling and need a clinician's own assessment; see which parasites mebendazole's labeling covers.

The dose and length of treatment are the prescriber's decision. We don't publish doses or schedules, and you should follow the directions on your own prescription label. For background on each medicine, see what is mebendazole and what is ivermectin. The side effects of mebendazole and ivermectin side effects pages list what each label reports.

Some infections need extra care. Anemia caused by hookworm or whipworm may need its own treatment. With pinworm, the CDC advises treating the infected person, their household members and their caregivers at the same time.

Preventing intestinal worms

The CDC's advice comes down to a few habits:

• Wash your hands with soap and water after using the toilet or changing diapers, and before handling food
• Wash, peel or cook raw fruits and vegetables
• Avoid soil and drinking water that may be contaminated with human stool
• Wear shoes where soil may be contaminated, to prevent hookworm
• With pinworm in the home, wash bedding and underwear and teach children to wash their hands often

Getting treated online

If a clinician has diagnosed one of these infections, or your history and test results point to it, a licensed provider can review a written health assessment through Get It Prescribed and decide whether mebendazole or ivermectin is appropriate for a labeled use. There is a one-time $50 consultation fee; mebendazole costs $3.50 per capsule and ivermectin $3.00 per tablet, and the prescriber decides the quantity. 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.

The medicines dispensed through Get It Prescribed are compounded preparations 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 products.

Our service is for adults. See a clinician in person instead if any of the warning signs above apply to you.

Related questions

What are the symptoms of intestinal worms in adults?

Many adults have none. When symptoms appear they can include anal itching at night (typical of pinworm), belly pain, bloating, diarrhea, tiredness from anemia, an itchy skin rash where larvae entered, or a worm seen in the stool. These signs overlap with many other conditions, so a test is needed to confirm a worm infection.

How do adults get intestinal worms?

Mostly by swallowing eggs, either from fingers and household items (pinworm) or from soil, food or water contaminated with human stool (roundworm and whipworm). Hookworm and Strongyloides larvae get in through bare skin that touches contaminated soil.

What is the treatment for intestinal worms in adults?

It depends on which worm a test finds. Pinworm, roundworm, hookworm and whipworm are the labeled uses of mebendazole, and intestinal strongyloidiasis is a labeled use of ivermectin. A clinician chooses the medicine and decides the dose and length of treatment.

Can adults treat intestinal worms with over-the-counter medicine?

For pinworm only, an over-the-counter medicine, pyrantel pamoate, is sold in US pharmacies; follow the package directions exactly. The other intestinal worms need a clinician's diagnosis and a prescription medicine.

How do I know which worm I have?

A test tells you. Pinworm is usually found with a tape test; roundworm, hookworm and whipworm with a stool ova and parasite test; and Strongyloides with repeated or specialized stool tests or a blood antibody test. Symptoms alone cannot reliably tell them apart.

Sources

• CDC: About Pinworm Infection — symptoms, how pinworm spreads, diagnosis and household treatment.
• CDC: About Soil-transmitted Helminths — roundworm, hookworm and whipworm, how they spread, symptoms and diagnosis.
• CDC: Clinical Overview of Strongyloides — clinical features and diagnostic testing.
• MedlinePlus: Ova and Parasite Test — how the stool parasite test works and why several samples may be needed.
• MedlinePlus: Pinworm test — how the tape test is done.
• MedlinePlus: Mebendazole — consumer drug information from the National Library of Medicine.
• MedlinePlus: Ivermectin — consumer drug information from the National Library of Medicine.
• DailyMed: mebendazole chewable tablet prescribing information — labeled uses: pinworm, whipworm, roundworm and hookworm.
• DailyMed: ivermectin tablet prescribing information — labeled uses: intestinal strongyloidiasis and onchocerciasis.
• FDA: Compounding and the FDA — Questions and Answers — what compounded preparations are and how they are regulated.