Strongyloidiasis: Symptoms and Treatment

Strongyloidiasis is an infection with Strongyloides stercoralis, a tiny roundworm that enters the body through bare skin touching contaminated soil and then lives in the small intestine. Most people have no symptoms at all, but some get belly pain, diarrhea, heartburn, a cough or itchy rashes, and testing and treatment decisions are made by a clinician; ivermectin is the medicine whose labeling covers intestinal strongyloidiasis.

What makes this worm unusual is that it can reinfect the same person from the inside, so an untreated infection can quietly last for many years. That is also why it matters more than most worm infections for anyone whose immune system is weakened.

What is strongyloidiasis?

Strongyloides is a parasitic roundworm. The CDC explains that its larvae live in soil, are too small to see without a microscope, and infect people by burrowing into exposed skin, most often bare feet. From there they travel through the body, reach the small intestine, and settle in to lay eggs.

Most of the young worms that hatch pass out of the body in stool. Some, though, mature inside the body and burrow back in through the wall of the intestine or the skin around the anus. Doctors call this autoinfection. It means a person can stay infected long after leaving the place where they caught it, without ever touching contaminated soil again.

Symptoms of strongyloidiasis

According to the CDC, most people with Strongyloides have no symptoms and may not know they are infected. When symptoms do appear, they can include:

• Pain in the upper belly, or bloating
• Heartburn or a feeling of fullness after eating
• Diarrhea that comes and goes, sometimes alternating with constipation
• Itchy skin rashes, including a raised, wandering rash around the buttocks, groin and thighs
• A dry cough or throat irritation, especially early in the infection
• In some people, weight loss, nausea or vomiting

A blood test may also show a raised level of eosinophils, a type of white blood cell that often goes up with parasitic infections. Because these symptoms overlap with many common stomach and skin problems, strongyloidiasis is easy to miss without testing.

Who is at risk?

The CDC lists these as the main risk factors:

• Living in or traveling to tropical and subtropical regions, such as Southeast Asia and the South Pacific
• Living in rural areas with warm, wet climates, or working in agriculture
• Contact with soil or sewage where human waste is not safely separated
• Living in a long-term care facility

MedlinePlus notes the infection is uncommon in the United States but does occur in the southeastern US, and that most North American cases are in people who have lived in or visited regions where it is common. Because of autoinfection, someone who lived in one of those regions years ago can still carry it today.

Why strongyloidiasis can become serious

For most healthy people, chronic strongyloidiasis is mild. The danger is for people whose immune systems are weakened. The CDC and MedlinePlus both warn that people taking corticosteroids (steroid medicines such as those used for asthma or lung flare-ups), people taking other immune-suppressing medicines, transplant recipients and people with certain immune conditions can develop hyperinfection syndrome or disseminated strongyloidiasis, where the worms multiply rapidly and spread through the body. The CDC describes these severe forms as life-threatening.

For that reason, clinicians may test, and sometimes treat, people from higher-risk regions before they start steroids or transplant medicines, even when they have no symptoms. Severe or spreading strongyloidiasis is a medical emergency and needs hospital care, not an online consultation. If you are very unwell, have a weakened immune system and new symptoms, or are on high-dose steroids, seek in-person or emergency care.

How strongyloidiasis is diagnosed

Diagnosis needs a clinician and a lab. The main tests are:

• Blood tests that look for antibodies to Strongyloides, along with a blood count that may show raised eosinophils
• Stool tests that look for larvae under a microscope. The CDC notes that a single stool test often misses the infection, so several samples, or specialized lab methods, may be needed

A positive antibody test can also reflect an older infection, so the clinician interprets the results alongside your history and symptoms.

How strongyloidiasis is treated

Strongyloidiasis is treated with prescription antiparasitic medicine. MedlinePlus names ivermectin and albendazole as treatment options. The prescribing information for the brand-name ivermectin tablet lists intestinal (non-disseminated) strongyloidiasis as one of its two labeled uses; the other is onchocerciasis, or river blindness. You can read more about the medicine itself in what is ivermectin and what is it used for.

Your clinician decides whether follow-up testing, such as repeat stool exams, is needed and what happens next. People with weakened immune systems need closely supervised care.

How much medicine, and for how long, is the prescriber's decision. We do not publish doses or schedules, and you should follow the directions on your own prescription label. Side effects and who should avoid ivermectin are covered in ivermectin side effects and who should not take these medications.

Can I get treated for strongyloidiasis online?

For an uncomplicated, intestinal infection, often one that has been confirmed by a test, a licensed provider can review your history through Get It Prescribed and decide whether ivermectin is appropriate. You complete a written health assessment and pay a one-time $50 consultation fee; the ivermectin tablet costs $3.00 per tablet, and the prescriber decides the quantity. See what ivermectin costs without insurance for the full breakdown. 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 walks through each step.

A prescription is never guaranteed. The ivermectin 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.

An online review is not the right route if you have a weakened immune system, take steroids or other immune-suppressing medicines, are pregnant or breastfeeding, or feel seriously ill. See a clinician in person.

Related questions

What are the symptoms of strongyloidiasis?

Most people have none. When symptoms appear, they usually involve the gut and skin: upper belly pain, bloating, heartburn, diarrhea that comes and goes, and itchy rashes, sometimes a wandering rash around the buttocks and thighs. A dry cough can occur early on. A clinician needs a blood or stool test to confirm it.

How do you get strongyloidiasis?

Through skin contact with soil that contains the worm's larvae, most often by walking barefoot. The larvae burrow into the skin and travel to the intestine. It is most common in warm, wet regions where human waste is not safely separated from soil. Rarely, it spreads in institutions or through organ transplants.

Can strongyloidiasis last for years?

Yes. Unlike most intestinal worms, Strongyloides can reinfect the same person from the inside, so an infection can continue for many years after someone leaves the area where they caught it, often without symptoms. That is why people from higher-risk regions are sometimes tested before starting steroid or transplant medicines.

What is the treatment for strongyloidiasis?

Prescription antiparasitic medicine, chosen by a clinician. Intestinal (non-disseminated) strongyloidiasis is one of the two labeled uses for oral ivermectin; albendazole is another option. A clinician may order follow-up stool tests afterward. Severe or spreading infection needs urgent hospital care.

How is strongyloidiasis tested?

With a blood test for antibodies to Strongyloides and with stool tests that look for larvae. A single stool test can miss it, so several samples or specialized lab methods are often needed. A positive antibody test can also reflect a past infection, so a clinician reads the results alongside your history.

Sources

• CDC: About Strongyloides — how the infection spreads, symptoms, risk factors and diagnosis.
• CDC: Clinical Overview of Strongyloides — chronic infection, hyperinfection syndrome and testing, for clinicians.
• MedlinePlus: Strongyloidiasis — National Library of Medicine overview, including US occurrence and treatment options.
• MedlinePlus: Ivermectin — consumer drug information from the National Library of Medicine.
• DailyMed: ivermectin tablet prescribing information — labeled indications and follow-up stool examination guidance.
• FDA: Compounding and the FDA — Questions and Answers — what compounded preparations are and how they are regulated.