Symptoms of Worms in Adults: Signs, Testing, and Treatment

That sudden, intense itch around your backside at 2 a.m. is often the first clue that something microscopic is living in your gut. Intestinal worms are more common than you think, and knowing the specific signs can save you weeks of confusion.

Global prevalence of soil-transmitted helminths: Estimated 1.5 billion people infected (WHO) ·
Most common worm in high-income countries: Enterobius vermicularis (pinworm), affecting up to 40 million in the US ·
Proportion of pinworm infections that are asymptomatic: Approximately 30% of cases show no symptoms ·
Number of worm species that commonly infect humans: More than 20 species, including roundworm, tapeworm, and hookworm

Four key facts, one pattern: most worm infections in adults fall into a small number of types, and the symptoms often overlap with common gut issues. The table below shows the diagnostic anchors.

What are the first signs of having worms?

Common early symptoms in adults

• Anal itching, especially at night, is the hallmark of pinworm infection (NHS).
• Abdominal pain, bloating, and diarrhea are common with various intestinal worms (Cleveland Clinic).
• Weight loss and fatigue can follow chronic infection (healthdirect Australia).

Anal itching and its connection to pinworms

• Female pinworms lay eggs at night on the skin around the anus, which is why itching is often nocturnal (CDC).
• Some people with pinworm infection have no symptoms at all (CDC).
• Pinworms can cause difficulty sleeping or restlessness (CDC).

Digestive symptoms: abdominal pain, bloating, diarrhea

• Abdominal pain can occur with pinworm infection, though it is not the classic symptom (CDC).
• Healthdirect lists abdominal pain, diarrhoea, tiredness and weakness, weight loss, and anaemia among possible symptoms of some worm infections (healthdirect Australia).
• Hookworms can cause abdominal pain, nausea, anorexia, iron deficiency anemia, and occult blood in stool in heavy infections (CDC).

The implication: nocturnal itching is your strongest giveaway. Without it, the symptoms are easy to confuse with IBS or food intolerance.

How can I check myself for worms at home?

Visual inspection of stool

• People may see small white worms in stool that look like pieces of thread (NHS).
• The NHS advises seeing a GP if a large worm, a piece of worm, or worm eggs are found in stool (NHS).
• Undigested vegetable fibers (e.g., banana, corn) are often mistaken for worms (Healthline).

The tape test for pinworm eggs

• A home tape test is a standard way to check for pinworms by pressing sticky tape around the anus after waking and before bathing or using the toilet (Mayo Clinic).
• Pinworm test: apply clear tape to the perianal area in the morning before washing (MedlinePlus).
• Home methods cannot replace a laboratory stool test for accurate diagnosis.

When a stool sample is necessary

• If you see worms or suspect infection but the tape test is negative, a stool sample at a lab can identify other species like roundworm or hookworm (CDC).
• The NHS says to seek GP advice if sickness, diarrhoea, or stomach ache last longer than 2 weeks (NHS).

The pattern: home checks are a good starting point, but they have blind spots. A negative home test doesn’t mean you’re worm-free if symptoms persist.

How do I know I need to deworm?

Clinical symptoms that suggest worm infestation

• Persistent anal itching, unexplained abdominal pain, or visible worms are clear indicators (Banner Health).
• Threadworm infection can also cause weight loss, bedwetting, and irritated skin around the anus (NHS).
• Larvae from some worms can cause pink or red skin lines called larva migrans or larva currens, which can itch intensely (healthdirect Australia).

Risk factors: travel, pets, poor hygiene

• Travel to areas with poor sanitation increases risk of hookworm and roundworm infections (CDC).
• Pets can transmit certain worms (e.g., roundworms) to humans via contact with feces or soil.
• Poor hand hygiene, especially after using the toilet or before eating, is a major transmission route for pinworms (NHS).

When to see a doctor vs. over-the-counter treatment

• For threadworms, the NHS recommends mebendazole purchased from a pharmacy and treating everyone over age 2 in the household at the same time (NHS).
• The CDC also recommends treating everyone in the same household and caregivers at the same time for pinworm infection (CDC).
• If you cannot take medicine, threadworms can be managed with hygiene methods for 6 weeks (NHS).

The trade-off: OTC mebendazole works well for pinworms, but for other types you need a prescription. Don’t self-treat if you’re unsure of the species.

What can be mistaken for worm in poop?

Undigested food fibers

• Undigested vegetable fibers (e.g., banana, corn) are often mistaken for worms (Healthline).
• Seeds and skins from fruits can also look like small worm segments.

Mucus or rope-like debris

• “Rope worm” is generally considered mucus accumulation, not a true parasite (Healthline).
• Intestinal mucus from conditions like IBS can be mistaken for worm material.

Yeast overgrowth and other benign material

• Yeast overgrowth (Candida) can produce white flecks in stool that some confuse with worm eggs.
• Consistent worm-like appearances with associated symptoms warrant a stool test.

What this means: seeing something in the toilet is alarming, but most of the time it’s harmless. The key is whether you also have itching, pain, or other systemic signs.

How do I know if I’ve got bum worms?

Symptoms specific to threadworm (pinworm) infection

• Intense perianal itching, especially at night, is the hallmark of threadworms (NHS).
• Threadworms are highly contagious via eggs on fingers, bedding, or toys (NHS).
• Threadworm infection can also cause weight loss, bedwetting, and irritated skin around the anus (NHS).

Transmission and self-inoculation

• Scratching the anal area transfers eggs to fingers, then to the mouth, causing reinfection (CDC).
• Eggs can survive on surfaces like bedding, towels, and toilet seats for up to 2 weeks.
• Good hand hygiene and short fingernails are critical to break the cycle.

Treatment and hygiene measures

• Treatment involves a single dose of mebendazole for the infected person and household contacts, plus strict hygiene (NHS).
• CDC guidance states pinworm treatment involves two doses of medication, with the second dose given two weeks after the first (CDC).
• Hygiene measures include washing hands, showering every morning, keeping fingernails short, and washing bedding and towels at hot temperature for several days after treatment (NHS).
• The NHS recommends not shaking clothing or bedding to avoid spreading eggs (NHS).

The implication: threadworms are a family affair. Skipping household treatment is the most common reason for persistent infections.

“The most common symptom of threadworms is an itchy bottom.”

— healthdirect Australia

“If you or your child has threadworms, everyone in the household should be treated.”

— NHS

“Symptoms of intestinal parasites include: Diarrhea, abdominal pain, gas, bloating, nausea, vomiting, and anal itching.”

— Cleveland Clinic

For an adult waking up with that unmistakable night-time itch, the choice is clear: run a tape test and treat the whole household if positive, or risk a cycle of reinfection that drags on for weeks. Ignoring symptoms won’t make them go away — and the 30% of asymptomatic carriers in your home will keep the cycle alive.