In some cases, yes. A handful of parasites are large enough or active enough to produce sensations you can genuinely feel, including movement under the skin, sharp stabs of pain, or crawling near the surface of the eye. But most parasitic infections produce no movement sensation at all, and the feeling of something crawling or wriggling inside you is more often caused by nerve signals, skin conditions, or other medical issues unrelated to parasites. Understanding which scenarios involve real movement and which don’t can help you figure out what’s actually going on.
Parasites You Can Actually Feel
A small number of parasitic infections do produce a noticeable sensation of movement. These are the most well-documented examples.
Botfly Larvae
The human botfly lays its eggs on the skin (often via a mosquito carrier), and the larva burrows into the tissue as it grows. People with botfly infections consistently report feeling movement inside the lesion, along with intermittent sharp, stabbing pain. A sensation of movement and itching are the most commonly reported symptoms. The larva feeds and grows under the skin for weeks, and the movement tends to come in bursts rather than being constant.
Hookworm Larvae in the Skin
Cutaneous larva migrans happens when hookworm larvae from animal feces penetrate the skin, usually on bare feet. The larvae can’t complete their life cycle in humans, so they wander through the upper layers of skin, leaving a visible red, raised, snake-like trail. The rash progresses at a rate of a few millimeters to about 2 centimeters per day. Most people don’t feel the larva itself moving, but the itching it causes can be severe enough to interfere with sleep and may continue for months. A related infection caused by Strongyloides moves much faster, traveling several centimeters per hour.
Eye Worms
The Loa loa worm, found in parts of Central and West Africa, is one of the few parasites people can literally see moving. Adult worms occasionally crawl across the surface of the eye, under the clear membrane covering the white. According to the CDC, these episodes are brief, painless, and may recur. A healthcare provider can sometimes diagnose the infection simply by spotting the worm during one of these migrations.
Pinworms
Pinworms are one of the most common parasitic infections worldwide, especially in children. Female worms migrate to the anal area, mostly at night, to deposit thousands of eggs. This physical migration causes intense itching around the anus. The sensation is real and directly caused by the worm’s movement and the eggs it leaves behind, not by an immune reaction. Many people (or parents of infected children) notice the itching follows a consistent nighttime pattern.
Parasites You Typically Can’t Feel
Most parasitic infections don’t produce any sensation of movement. Large roundworms (Ascaris) can grow to 30 centimeters or more inside the intestines, yet the CDC notes that many infected people have few or no symptoms at all. When symptoms do appear, they tend to be general abdominal discomfort or pain rather than a feeling of something moving. In heavy infections, people may pass a worm in their stool or cough one up, but this is different from feeling ongoing movement inside the body.
Scabies mites are another example. These tiny parasites burrow into the top layer of skin, but you don’t feel them digging. The intense itching and rash that scabies causes are actually a delayed allergic reaction to the mites’ waste products, appearing three to six weeks after the initial infection. By the time you notice symptoms, the mites have been there for over a month.
Tapeworms, flukes, and many other internal parasites can live in the body for years without producing any sensation of movement. Their symptoms, when they occur, come from inflammation, nutrient theft, or organ damage rather than from anything you’d describe as “feeling them move.”
When It Feels Like Parasites but Isn’t
The sensation of something crawling on or under your skin has a medical name: formication. It feels convincingly real, like insects or worms moving just beneath the surface, but it originates from your nervous system rather than from any organism. This is far more common than actual parasitic movement, and several conditions can trigger it.
Peripheral neuropathy, or nerve damage, is one of the most frequent causes. Damaged nerves misfire and send signals your brain interprets as tingling, prickling, crawling, or movement. Diabetes is a leading cause of this type of nerve damage, but vitamin B12 deficiency, multiple sclerosis, thyroid disorders, and several other conditions can produce the same effect. The sensation can be persistent and localized, which makes it especially easy to mistake for something alive under the skin.
Substance use is another well-documented trigger. Methamphetamine and cocaine use can cause intense crawling sensations, sometimes severe enough that people scratch or pick at their skin trying to remove what they believe is an infestation. Alcohol withdrawal can produce similar symptoms. Certain prescription medications, including some antibiotics, antifungals, and steroids, have also been linked to formication as a side effect.
Dehydration, anxiety, and simple transient nerve misfires can all cause brief episodes of skin crawling that resolve on their own. If you’ve ever felt a sudden itch or twitch that seemed to move across your skin, that’s paresthesia, and it’s usually harmless.
How Doctors Tell the Difference
When someone reports feeling parasites moving, doctors follow a specific process to determine whether a real infection is present. A thorough physical exam looks for visible signs: the snaking rash of larva migrans, a botfly nodule, a worm visible in the eye, or pinworm eggs detected with a tape test. These infections leave physical evidence.
Blood tests can also help. An elevated level of eosinophils, a type of white blood cell that increases during parasitic infections, suggests the immune system is responding to an actual organism. Travel history matters too. Many parasites that cause noticeable movement are found in tropical or subtropical regions, so recent travel to endemic areas raises the likelihood of a real infection.
When a thorough exam, lab work, and history turn up no evidence of infection, and the crawling sensation has persisted for six months or longer, doctors consider a condition called delusional parasitosis. This is a recognized psychiatric condition where the sensation of infestation feels completely real but has no physical cause. It’s important to note that this diagnosis requires first ruling out every plausible physical explanation. Misdiagnosis can go in both directions: real infections sometimes get dismissed as psychological, and non-parasitic crawling sensations sometimes lead to unnecessary treatments.
What to Pay Attention To
If you’re experiencing a sensation of movement under your skin or inside your body, a few details can help you (and your doctor) sort out the cause. Visible skin changes like a moving rash, a growing nodule, or a raised trail strongly suggest a real parasitic infection. Nighttime anal itching, especially in a household with children, points toward pinworms. A crawling sensation with no visible skin changes, particularly if it’s widespread or has lasted weeks to months, is more likely to have a neurological or systemic cause.
Your recent history provides important clues. Walking barefoot on tropical beaches, exposure to freshwater in endemic areas, insect bites during travel, or contact with animal feces all increase the chances of a genuine parasitic infection. If none of these apply and the sensation is your only symptom, nerve-related causes become much more probable. A blood count checking for eosinophils and a basic metabolic panel looking at B12 levels and blood sugar can quickly narrow down the possibilities.