Late last year, Pat Hannon started waking up in the middle of the night with an excruciating itching sensation on her legs. “It was like a mosquito bite on steroids,” she said. Hannon was convinced that insects were feasting on her. But every time she leaped out of bed, turned on the lights and flipped down her bedsheets, there was nothing.
She washed the bedding, vacuumed the mattress and sprayed her legs with repellent. She called a local pest control company, which said she could pay $500 to hire a beagle that could supposedly sniff out bed bugs. She started sleeping in a recliner in the living room, thinking, they won’t find me here.
At her lowest moment, she considered hiring someone to fumigate her home. “I was getting desperate,” she said. “I thought, ‘Oh, so what, I’ll get lung cancer.’” At least the itching might stop.
Hannon went to urgent care with her problem, as it would have taken months to get an appointment with a dermatologist. The physician told her he didn’t see anything wrong with her. “I felt like an idiot,” she said. “I thought, I have to convince this guy that I am not crazy.” But “he spent two minutes with me and he was gone.”
Like many Americans, Hannon was living without a diagnosis to make sense of her suffering. Over the past eight years, I interviewed dozens of patients, doctors and other experts for a book examining why a person’s search for health answers can stretch on for months, years or even a lifetime. For too many people, diagnoses are delayed, incorrect or not made at all. Without one, people struggle to get effective treatment and insurance coverage. Desperate for relief, some turn outside the medical system for answers — a precarious, isolating place to be.
The diagnosis crisis affects millions of Americans. According to a report from the National Academies of Sciences, Engineering and Medicine, “most people will experience at least one diagnostic error in their lifetime, sometimes with devastating consequences.” This kind of impasse can be especially common for people with so-called medically unexplained illnesses, or conditions marked by many symptoms (fatigue, brain fog) but few visible signs (rashes, test results).
Because of extraordinary medical advances, there are now a wide range of tools with which to diagnose people, from sophisticated imaging to genetic sequencing. That makes it all the more fraught when doctors still can’t figure out what is going wrong with someone. Patients feel frustrated or dismissed. Physicians feel uncertain about their ability to help the person in front of them.
Desperate for relief, Hannon had also reached out to local insect researchers. One of her messages landed in the inbox of Gale Ridge, an entomologist who identifies pests with her colleague Katherine Dugas at the Connecticut Agricultural Experiment Station, a state-funded research institution in New Haven.
On a typical day, they greet farmers bringing them ticks, real estate agents with mysterious roaches and anxious homeowners concerned about a weird bug. But starting in the early 2000s, Ridge more regularly saw a different kind of visitor: people convinced that bugs were not inside their homes but on or inside their bodies.
At first, there were one or two such people a year. Then dozens. Then hundreds. In 2025, Ridge says, she received 1,610 inquiries from such people. After doing some research, she learned that some of them might suffer from delusional infestation — an unshakable belief of being infested by insects or parasites.
Many of the potential D.I. cases that Ridge now encounters are referred to her by perplexed pest management professionals or concerned family members who find her online. In 2017, Eric Boodman, a journalist for STAT News, wrote a moving profile of Ridge, and the story brought many more people into her office. Sometimes they have mutilated themselves to extract the phantom parasites.
She’s seen suffering from all kinds: women in their 50s, veterans, business owners and homeless people. “This is a condition that will humble any person in any walk of life,” said Ridge. She’s haunted by the case of a respected cancer researcher who believed that insects were burrowing under his skin. He tried medications, exterminators, even soaking himself in a bathtub of insecticide.
“These people are in the middle of a battle zone in their lives,” Ridge said. “They are suffering from something unexplained, and the medical profession has let them down.”
In the United States, health care is often fragmented, leaving patients to shuttle information among specialists who may not communicate with one another. For conditions that are ambiguous and don’t fit neatly into one specialty, this lack of coordination can be a major obstacle to diagnosis and recovery. Insect experts like Ridge end up seeing people who clearly need help — medical or psychological — but have nowhere to send them. Appointments can take months to book, and some doctors simply don’t want those referrals.
Ridge believes that a vast majority of the people who seek her help have something physically wrong — like an undiagnosed medical condition — but are misidentifying the cause. Later she may learn it was an autoimmune disease, an allergy, nerve damage or a thyroid condition, all of which can produce an itching or even crawling sensation. Typically, she says, she sees upticks around periods of uncertainty — for instance, the 2008 financial crisis, the Covid-19 pandemic, the 2024 presidential election.
“I was in many ways unwillingly brought in because I am the entomologist,” she said. “I’m the end of the road for many of these people.” But she also realized that if she didn’t find a way to help them, no one would.
Delusional infestation is one of the darkest embodiments of the chaos that accompanies medical uncertainty. While it’s an extreme, complicated and relatively rare phenomenon, the experience of living undiagnosed or incorrectly diagnosed is not. Ridge has it right: People are going to her as a last resort, usually after seeing a revolving door of health care providers. These people are experiencing something excruciating and yet their condition remains medically unexplained.
Much of the academic and scientific literature on delusional infestation comes from people like Ridge who learn how best to respond through trial and error and pass that knowledge on to others. “This is not technically part of our job,” said Jody Green, an entomologist at the University of Nebraska-Lincoln who sees delusional infestation cases. “But if we know that people can turn a corner and get better if they get help quickly, then we should be a part of that.”
Over the years, delusional infestation has gone by several names, including delusional parasitosis and Ekbom syndrome. Cases are often classified as either primary or secondary. A diagnosis of primary delusional infestation typically requires that the symptoms persist for more than a month, that the person has never been diagnosed with schizophrenia and that he or she is otherwise physically functional. A substantial proportion of cases appear to be secondary, meaning they are experienced alongside or as a consequence of an underlying medical, psychiatric or drug-related condition.
Many experts view delusional infestation as existing on a spectrum, ranging from brief and minimally disruptive to life destroying. Dr. John Koo, a dermatologist and a psychiatrist at the University of California, San Francisco — and one of the few medical experts who regularly takes on these cases — helped develop a system to track the progression of the disease. At one end is essentially normal behavior. At the other is “terminal delusion,” a trajectory he describes as a “descent into hell.”
In 2024, Ridge, Koo and several other experts published a comprehensive guide to delusional infestation for physicians, entomologists and other insect experts. The hope was to raise awareness of the condition and ideally prompt a bigger network of support inside the medical establishment, which has so far been a struggle.
“The silence is deafening. I cannot get through to the medical community,” said Ridge, adding, “This particular condition depends on those silos breaking down, and allowing dermatologists to talk to the neurologists, to talk to the parasitologists.”
At a delusional infestation conference in Knoxville, Tenn., in January, Ridge, Koo, Green and a number of other insect professionals and health care providers shared experiences and discussed best practices. Entomologists from Tennessee, Florida, North Carolina and elsewhere reported encountering cases every week. Many participants said they felt overwhelmed and ill equipped to help and wanted more collaboration with doctors and guidance on how to respond.
A presenter shared graphic images of a man who picked at his skin with a pocketknife; a registered nurse who used tweezers to pull off scabs; another man who sliced his neck with scissors while searching for worms. People of all backgrounds are susceptible. One professional at a parasite identification laboratory said he had encountered medical professionals seeking help for themselves.
There was something touching about the concern with which conference attendees discussed the people in their community they wanted to assist, without judgment. “If I can help somebody get rid of their bug problem, I’ve done my job,” Joey Webb, an exterminator in Greeneville, Tenn., told me. He said he considers himself a professional problem solver. “So when I run into somebody who seems to have D.I., I can’t help them. It’s concerning, tragic.”
In the United States, the average doctor’s appointment lasts around 18 minutes, and the average primary care doctor sees about 20 patients a day. That can be enough time if a patient has, say, a clear case of shingles. But the encounter becomes far more challenging when a patient arrives complaining of symptoms with no obvious cause.
Doctors have roughly 17,000 diagnostic disease categories to choose from, most of which share some of the same 150 to 200 common signs and symptoms. A headache could be a symptom for some 300 diseases and chest pain could be a symptom of 25. A symptom like fatigue could have countless possible causes. “There are several sources of frustration for a doctor when a patient walks in and says, ‘I just have not had my usual energy, and I’m not able to function at home or at work the way I used to,’” said Dr. Anthony Komaroff, a leading expert in myalgic encephalomyelitis/chronic fatigue syndrome, or M.E./C.F.S., at Harvard.
Doctors are trained to become very good at elucidating the most likely cause of a person’s symptoms based on knowledge of human biology and the history of the person in front of them. They usually get it right: A diagnosis is made and a treatment plan follows. But errors still occur. When a patient has no visible signs of disease and no test results or abnormal scans that point in a specific direction, the available options narrow. A doctor may wonder whether another specialist might see something she cannot, or whether the illness itself is not yet fully understood by medicine or science. In either case, both doctor and patient can feel unsatisfied or worse.
Conditions like delusional infestation are not simple cases with tidy solutions. But medicine has much to learn from the methods that unintentional experts like Ridge and Dugas, her colleague in Connecticut, have refined over the years. The duo developed their own protocol to help the people who come to them understand that their bodies are not infested.
Step 1 is to take their suffering seriously. Ridge and Dugas explain how to take samples of what the clients believe is evidence of bugs on their skin or in their environment: Press a piece of Scotch tape onto the area where the biting or pricking sensation is strongest, gently lift it off and stick it onto a glass jar, labeled with the location, time and date.
Ridge and Dugas then place each specimen — which may ultimately be a piece of hair or lint — under a microscope attached to a large camera and look at them with the client. During the meeting, the entomologists explain that insects are animals. They have brains, muscles, a digestive system. They need to breathe air to survive and therefore cannot burrow into the skin and live there. “I am providing them with time,” explained Ridge. “By sitting with them and being with them rather than talking at them, we develop a relationship of trust.”
Ridge has observed a critical window to intervene. “If I have a client who is dealing with this less than six months, I can turn them,” she said, meaning help them to realize insects are not the issue.
The internet makes her work harder. What may start as innocent Googling can become an accelerant for people’s mounting distress: Artificial intelligence chatbots deepen preoccupations, forums turn into echo chambers, algorithms feed confirmation bias and opposing views disappear. If sufferers are stuck in their belief system long enough, Ridge said, “it’s almost impossible to get them back.”
Ridge said that, with her protocol, she has been able to get many of the people she sees to re-engage with the medical system and understand that what they’re dealing with is not likely to be bugs under their skin, even before they’d qualify as a case of delusional infestation.
In an email warning Hannon not to self-treat with pesticides and urging her to “please stay away from the internet” until they could figure out what was happening, Ridge asked a simple question: Why did Hannon believe bugs were biting her if she had never seen them?
“I didn’t have a good answer to that,” Hannon acknowledged. “Her question really turned my thinking around to realizing it’s not an insect.”
Ridge shared her guidelines for taking skin samples, but Hannon was already wondering if perhaps she had been mistaken about the biting. She tried switching her soap and lotion. Soon, the sensation abated. Perhaps it had all been severe skin irritation. Thankfully, Hannon had only dealt with the “bug” problem for a couple of weeks. Her experience exemplifies how early attention can resolve suspicions before they take hold.
Ridge had seen far too many people who, without early care, descended into a world of misery and isolation. Hannon was aware of that possibility and embarrassed by the situation — she hadn’t told her friends about it. But to get relief, she said, “I would have done anything.”
In my reporting on complicated diagnoses, whether for an unusual cancer, a rare genetic disorder or a condition that’s not yet fully understood by science, I was struck by how similar people’s stories ultimately were. They described moving from one doctor to another, retelling their history each time. They spoke of monthslong waits for appointments, seemingly endless tests and, along the way, multiple misdiagnoses and fruitless treatments.
The problems are not the fault of a single doctor or medical team. Rather, our current medical model doesn’t offer clear pathways for people with conditions clouded in medical uncertainty. In the words of the medical sociologist Sarah Nettleton: “Medicine serves to restore coherence.” This is why when medicine fails to provide a clear answer, the result can be mayhem.
Fixing this requires structural change and humility. Too often, a physician sends a patient home confident in the diagnosis, never learning that it was incorrect or that the patient sought care elsewhere because the symptoms were unresolved. Health systems can do more to promote diagnosis collaboration across medical teams and to build in meaningful tracking-and-feedback mechanisms around diagnostic accuracy. Without feedback, there is little opportunity to learn from mistakes and improve.
Progress also depends on fostering a culture that is more comfortable with uncertainty. All prospective doctors should learn in medical school how to communicate uncertainty honestly to patients and engage seriously with ambiguous or complex conditions early in their training, so they are comfortable when they inevitably see them. Health systems could also open clinics where experts across specialties take on challenging cases together. Models for this kind of care already exist and could be more widely adopted.
When answers are uncertain and unfold slowly, bedside manner becomes a part of the experience of illness. One father likened his daughter’s rare disease diagnosis by a group of experts who cared to having an umbrella in a rainstorm. “The diagnostic process is run by humans and humans are imperfect,” he told me. “It’s not going to be perfect. That’s not feasible, and science is limited.” But when you are in the hands of people who care, “you forget what it’s like to be wet for a moment.”
How different might Hannon’s experience have been if the urgent care doctor had spent just a little more time with her? He told her he couldn’t find anything wrong, but rather than feeling reassured, she left the appointment feeling minimized and without relief.
A greater dose of humanity could go a long way toward solving the diagnosis crisis. Not just empathetic clinicians, but also a more humanely organized system. Complex cases require time, continuity and collaboration across disciplines, all of which are in too short supply. Doctors want this, too. Often there won’t be simple answers, but people still need someone willing to sit with their questions.
Alexandra Sifferlin is the health and science editor for Opinion and author of the forthcoming book “The Elusive Body Patients, Doctors, and the Diagnosis Crisis,” from which this essay is adapted.
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The post They Feel Bugs Inside Them. Doctors Don’t Know Why.
