What Are PANS and PANDAS?

Parents use words like “abrupt,” “overnight,” and “out of the blue.” The symptoms, they say, went “from zero to 60.” The child, who had been happy and untroubled, “fell off a cliff.”

Parents can often tell you the exact day a child started washing their hands until they’re raw, opening and closing the door endlessly, asking the same questions over and over. It’s called acute-onset OCD, and the onset can often be linked to strep or some other kind of infection. It’s thought that the acute OCD symptoms are caused by brain inflammation, when the body’s immune system mistakenly attacks healthy brain cells.

Sudden-onset OCD, along with symptoms that can include restricted eating, anxiety, and irritability, can indicate conditions called PANS or PANDAS. If the symptoms are associated with a strep infection, which is most often the case, it’s called PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections). If it’s not related to a strep infection, it’s called PANS (pediatric acute-onset neuropsychiatric syndrome). PANS is essentially an umbrella term that includes PANDAS as well as other cases of these abrupt-onset symptoms with undetermined causes. Some (but not all) PANS cases have been linked to infections other than strep, including mono, pneumonia, and flu.

While PANDAS has been studied and treated for decades, it has been slow to be accepted by the medical and psychiatric community. The American Academy of Pediatrics finally issued a report in 2025 acknowledging that PANS is a legitimate diagnosis but advising pediatricians to avoid some of the treatments that are currently in use, on the grounds of insufficient data.

In most cases of obsessive-compulsive disorder, the symptoms come on gradually. Children begin to experience fears that are disturbing, and they become obsessive — they feel they can’t escape them — over time. To manage these obsessive fears they develop rituals called compulsions, such as counting or touching things repeatedly or washing their hands. They typically hide their rituals as long as they can. Eventually, the obsessions and compulsions take over more and more of their life, until they can’t hide them any more.

But with PANS and PANDAS the OCD symptoms appear suddenly and are accompanied by other confusing and disturbing symptoms.

Signs a child might have developed PANS and PANDAS include:

• Acute-onset OCD
• Restrictive eating
• Severe separation anxiety
• Handwriting suddenly becomes unrecognizable
• Drawings look like scribbles
• Wetting the bed and frequent urination  
• Can’t manage the math or reading they could do effortlessly the previous week
• Irritable
• Oppositional behavior
• Emotionally erratic
• Behavioral regression, such as babytalk, needing help for basic grooming tasks
• Sleeping problems
• Panic attacks
• Suicidal thoughts

This sudden-onset OCD — along with a host of other disorienting symptoms — was first identified in the late 1990s by Susan Swedo, MD, the chief of pediatrics and developmental neuroscience at the National Institute of Mental Health (NIMH). It was named PANDAS — that is, pediatric autoimmune neuropsychiatric disorder associated with streptococcus — because onset seemed to be linked to infection, and strep was the most common of those infections, as well as one that had already been examined extensively. “A disease mechanism is easier to define for a single organism,” Dr. Swedo explains. That said, they knew at the time, Dr. Swedo adds, that some other infections can also be linked to this set of symptoms.

PANDAS is often diagnosed in children who have what doctors call “occult” strep infections — that is, children who can be “carriers” of the infection to others, but do not show symptoms, and hence don’t get treatment. It happens in about 1 in 1,000 children, and three times as often in boys than girls, explains Dr. Swedo. It’s defined as a pre-pubertal condition, since most kids, by the time they hit adolescence, have developed immunity to strep, so onset isn’t likely to occur after that, though PANDAS symptoms will continue to occur intermittently. Sometimes these symptoms grow worse with each flare-up, or what doctors call “exacerbation.”

The theory behind PANDAS is that the strep bacteria “hide” from the immune system by mimicking the child’s own cells. “It’s a kind of camouflage to evade detection by the immune system,” Dr. Swedo explains. The immune system eventually recognizes the bacteria, and produces antibodies to fight them, but because of the similarities to human cells, those antibodies in turn sometimes “misrecognize” molecules in a child’s own body and attack them. In the case of rheumatic fever, for instance, they attack the heart. In the case of PANDAS, the theory goes, it’s the brain — specifically the basal ganglia, which is where OCD symptoms are thought to originate.

While there are animal and human studies that demonstrate the link between the infection and the OCD-like symptoms, not all researchers in the field were initially convinced that the link was adequately demonstrated. And they were especially leery of moving too quickly to accept the link because of the potentially negative effects of putting kids on antibiotics for signs of psychiatric symptoms.

With this controversy as the backdrop, in 2010 Dr. Swedo and her colleagues at the NIMH proposed a new, broader category that describes the set of symptoms without a specific link to strep. It’s called PANS (pediatric acute-onset neuropsychiatric syndrome), and it applies to children and adolescents who suddenly develop abrupt-onset OCD symptoms or restrictive eating behaviors, along with other psychiatric symptoms — without any link to a cause.

The effect of this new category was twofold: First, to acknowledge that other infections besides strep — notably mono, mycoplasma pneumonia (walking pneumonia), and the flu (such as H1N1) — have been linked to this set of symptoms. Second, to bridge the controversy by separating areas of agreement — the set of symptoms  — from disagreement over etiology. (For example, there have been reported cases of PANS associated with Lyme disease and COVID-19, but the evidence so far is not strong enough to include these infections as possible causes.) PANS has been successful in enlarging the definition, Dr. Swedo notes, but not in quieting the controversy.

In January 2025, the AAP issued a clinical report on PANS that acknowledged PANS as a legitimate diagnosis, outlined symptoms, and offered pediatricians clinical guidelines for diagnosis and treatment. “The AAP recognizes that PANS is likely a valid diagnosis, although the diagnostic process is challenged by a lack of well-accepted evidence to guide the clinician.”  

The group described PANS as “a condition that involves a constellation of psychiatric and neurologic symptoms that present simultaneously and in rapid onset, the cause or causes of which are unknown. Although the cause is still under investigation, the manifestations may follow a recent infection.”

The list of infections that have been cited as possible triggers of PANS-like symptoms include group A streptococcus, mycoplasma pneumoniae, influenza, and sinusitis. “Not all cases of PANS are reported to be triggered by an infection, however, and no single microbe has been associated with the onset of PANS.”

A consortium of experts has developed what are  considered a “working draft” of diagnostic criteria for PANS, which have been mirrored by the AAP.

The criteria for PANS are the abrupt onset or recurrence of OCD or severely restricted food intake, along with abrupt onset at least two of the following seven categories:

• Anxiety
• Emotional dysregulation
• Irritability, aggression, and/or oppositional behaviors
• Behavioral regression
• Academic deterioration
• Motor/sensory abnormalities (including heightened sensitivity to sensory stimuli, hallucinations, dysgraphia, and complex motor and/or vocal tics)
• Somatic abnormalities (including sleep disturbances, enuresis, or urinary frequency)

A diagnosis of PANDAS requires the symptoms to be associated with a recent untreated strep infection. The criteria for PANDAS are:

• Abrupt onset of OCD and/or tics
• A relapsing-remitting, episodic symptom course
• Symptom onset prior to puberty (average of 6–7 years)
• Presence of neurologic abnormalities, such as tics, fidgeting, or involuntary “piano playing” finger movements
• Symptoms started soon after a group A streptococcus infection

The PANDAS Physicians Network, a multi-disciplinary coalition of medical professionals experienced with PANS and PANDAS, has established diagnostic guidelines and treatment protocols for PANS and PANDAS based on the severity of cases. PPN describes treatment as “a three-pronged approach that addresses the source (infections), the immune system dysfunction, and the symptoms.”

According to the PPN recommendations, inciting infections should be targeted with antibiotics. The OCD and other psychiatric symptoms should be treated with behavior therapy (specifically exposure with response prevention) and, if necessary, medication. If SSRIs are used, the PPN advised that they be started at “an extremely low dose with a very slow upward taper to avoid activation, agitation, akathisia, and other adverse effects of the drugs.” Anti-inflammatories, including NSAIDs and corticosteroid bursts, may be beneficial to hasten recovery and minimize residual symptoms.

The PPN advises that severe cases can be treated with options that include long-term antibiotics, plasmapheresis (the exchange of blood plasma), or IVIG (intravenous immunoglobin), which give children antibodies from a myriad of donors.

The AAP does not support the use in treatment of long-term antibiotics, plasmapheresis, or IVIG, on the grounds that there is insufficient evidence of their effectiveness. The report urged the development of large, multicenter studies. “Until that goal has been reached, the AAP recommends a deliberate and cautious approach, grounded in evidence, and focused on helping children who have the symptoms of possible PANS.”

Tom Insel, MD, a clinical psychiatrist, neuroscientist, and former director of the National Institute of Health, puts continuing skepticism about PANDAS in a historical context. “There is a history of reluctance to accept an infectious cause of a psychiatric or behavioral disorder, and the debate over PANDAS has been going on almost two decades,” he wrote in 2012. He describes the PANS category as a move “toward consensus on some of the larger issues, such as a broader concept of ‘acute and dramatic’ onset of the same profile of psychiatric symptoms identified in PANDAS” — but without positing any cause.

“The onset has not always been linked precisely with a strep infection, and the critical increase in antibodies to strep has not been evident consistently,” Dr. Insel notes. “Nevertheless, immune-based treatments have proven successful, leading to the growing acceptance of the concept of PANDAS.”

Nancy Myers, a mother who had to fight her practitioners to get antibiotics to treat her son, is avidly following the debate in the mental health establishment. “I think ultimately we’re going to get the medical community turned around on this,” she says. “I’m just hoping it’s going to be fast enough for a lot of people.”er studies. “Until that goal has been reached, the AAP recommends a deliberate and cautious approach, grounded in evidence, and focused on helping children who have the symptoms of possible PANS.”