Complete Guide to PANS and PANDAS

For most children with OCD, symptoms come on gradually. At first children are often able to hide both their fears and the rituals they develop to calm them. Eventually the fears become too overwhelming, and the rituals too time consuming, to conceal from parents.

But there is another kind of OCD in which full-blown symptoms come on virtually overnight. It’s called “acute onset.” This happens to some young children after they’ve had an infection, usually strep. It’s thought to be the result of the child’s immune system erroneously attacking brain cells. It is accompanied by other symptoms, which can include restricted eating, anger, panic attacks, and depression.

“Parents, with great reluctance, talk about their child being possessed, either by a demon or by aliens,” says Susan Swedo, MD, a pediatrician who has been studying the syndrome for decades.

PANS and PANDAS are conditions that involve sudden, severe OCD and other disturbing symptoms, often following an infection like strep.

PANS (pediatric acute-onset neuropsychiatric syndrome) is a more general term that does not specify the cause of the symptoms. It’s called “acute onset” because the behavior changes come on suddenly, reaching full-scale intensity within 24 to 48 hours. It’s a syndrome because there are quite a few other symptoms that appear alongside the sudden, severe OCD.

PANDAS (pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections) is a more specific term used when the triggering infection is strep. PANDAS is a subgroup of PANS.

Children especially at risk are those who have what doctors call “occult” or hidden strep infections — that is, children who can be “carriers” of the infection but don’t get symptoms themselves and hence don’t get treatment.

PANS cases have also been linked to other infections, including mononucleosis, mycoplasma (walking pneumonia), and the flu (such as H1N1). There are reports that they have been triggered by Lyme disease and COVID-19, but there is insufficient evidence for a clear link.

PANS and PANDAS are episodic disorders. Symptoms may disappear for extended periods then reappear, stimulated by a later exposure to strep or some other bacteria or virus. Symptoms may get increasingly severe with multiple recurrences.

Signs of PANS and PANDAS include changes in mood, behavior, and sensory and motor function in children:

• 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

While this syndrome has been recognized for decades, the link between the symptoms and an infection has been the subject of intense controversy, with some researchers and clinicians claiming insufficient evidence, and denying children treatment to fight the sometimes elusive infection.

Dr. Swedo, who headed the pediatrics and developmental neuroscience branch of the National Institutes of Mental Health until she retired in 2019, first identified PANDAS in 1998, and has been in the vanguard of research and advocacy ever since. The larger category, PANS, was added in 2010 to create expert consensus on the existence of the syndrome, despite the debate over causes. Cases that are linked to a strep infection can still be called PANDAS. Those that are linked to another infection or have no apparent cause are called PANS.

There is now broad acceptance that PANDAS is, like rheumatic fever, a misdirected immune response to the strep bacteria, which mimics human heart or brain tissue. The immune system attacks the heart (in the case of rheumatic fever) or brain (in the case of PANDAS), causing this array of mental health symptoms.

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.

“What this is not is garden variety OCD, Tourette’s, ADHD, conduct disorder — anything else,” explains Dr. Swedo. “We’re talking about a six-year-old, seven-year-old, maybe as young as three or four, who undergoes an acute behavioral change, a very, very dramatic onset.”

Acute-onset OCD might take the form of a child suddenly engaging in endless handwashing, checking things like locks and doors, counting or ordering things, repetitive questioning, or asking for constant reassurance. Many children with PANS become obsessive about food, severely restricting what they will eat because of acute fears of contamination, choking, or vomiting. This can develop into anorexia, and can result in extreme weight loss, necessitating hospitalization and the use of a feeding tube.

Separation anxiety can also appear suddenly, sometimes so overwhelming that a 10-year-old or even a 14-year-old suddenly has to start sleeping with a parent. And panic attacks are common. “In those first few days, the child is in state of near-constant panic,” Dr. Swedo adds. “These changes are not subtle.”

All children with the disorder have acute onset of OCD symptoms or eating restrictions. But they also have a debilitating and baffling set of other neurological symptoms with similarly sudden onset. To be diagnosed with PANS they must have two of the following seven criteria:

• Separation anxiety, panic, other forms of anxiety
• Behavioral regression: Kids suddenly acting much younger than they should for their age, such as reverting to baby talk.
• Emotional lability: These children can be severely depressed, even suicidal
• Irritability, aggression and/or oppositional behaviors
• Deterioration in school performance: Sudden decline in math and reading competence, memory and concentration; increase in hyperactivity
• Motor or sensory abnormalities: Their handwriting and drawing deteriorates dramatically, they may develop tics, and they may be distressed by noise or light
• Somatic symptoms: These include sleep disturbances, bedwetting, and other changes in urinary frequency or intensity 

Parents’ first stop when they experience such a dramatic behavior change is usually the pediatrician, or in extreme cases, the emergency room, Dr. Swedo notes. She recommends that you refrain from insisting to the doctor that your child has PANS, and bringing along articles on the disorder as backup, since medical professionals tend to be skeptical of a parental rush to diagnosis.

The best way to present this, she says, is: “I’m really worried about my child’s brain. There’s been an abrupt change in his behavior. This is what I’ve seen at home. It’s completely out of character.” The goal, as she puts it, is to partner with the doctor in terms of let’s figure it out together. PANS is one possible explanation for the sudden changes in behavior, but your physician will want to consider others as well.

In the past, pediatricians and other doctors have often dismissed families describing acute-onset OCD, Dr. Swedo said, assuming that parents must have missed earlier, less severe symptoms. PANS and PANDAS is now much more widely recognized, but skepticism and unfamiliarity persist.

It’s also good to check with your child’s teacher or school to see if strep has been going around. A child doesn’t have to have a sort throat or other symptoms of strep to have an infection — some kids never get symptomatic.

If a child has urinary symptoms, Dr. Swedo recommends urinalysis and urine culture. She recommends a throat culture to look for strep, and an exam to see if an occult, or hidden, strep infection is observable.

If the rapid strep test is positive, she recommends a three-week course of antibiotics, to aggressively treat a possible sinus infection This can be supplemented by a 5-7 day course of NSAIDs.

And Dr. Swedo also recommends that the pediatrician schedule a follow-up visit for three days later, to check in with the family. “The family stress is through the roof with this syndrome — by some measures higher than kids who’ve been diagnosed with leukemia,” she notes. “So a physician treating the medical causes should also make a referral, immediately, to a psychologist or psychiatrist— whatever is available in your area.”

Many children respond within the first week of the antibiotic treatment. The longer the symptoms have been active before the child starts treatment, the longer the response may take. If the symptoms disappear, you finish the course of antibiotics and then practice what Dr. Swedo calls “watchful waiting.” Some kids, however, don’t respond to the antibiotic treatment alone. And many will have later episodes when symptoms recur, triggered by another infection.

Treatment involves targeting what Dr. Swedo calls the three S’s: “the symptoms, the source, and the system.”

• The treatment for the symptoms — OCD and other forms of severe anxiety — is cognitive behavioral therapy (specifically, exposure and response prevention) and possibly an anti-depressant medication called a selective serotonin reuptake inhibitor or SSRI. These treatments have been shown to be effective in reducing the symptoms, but they do not target the source of the problem.
• The treatment for the source — the infection — is a course of antibiotics.
• The system refers to the immune system, which is thought to be attacking the brain and generating these neuropsychiatric symptoms. The first-line treatment for the misfiring immune system is with IVIG, or intravenous immunoglobulin. IVIG is made from healthy blood plasma and is thought to balance the immune system. IVIG is recommended only for severe cases in which repeated courses of antibiotics combined with CBT and SSRIs were not successful in stopping the flare-up of symptoms.

If IVIG, in turn, is not successful, children are treated with plasmapheresis (the removal, filtering and return of blood plasma). A review of 40 patients treated with plasmapheresis showed an average improvement of 65 percent at 6 months following treatment, and 78 percent at longer-term follow-up.

Dr. Swedo notes that these three targets for treatment — symptoms, source, and system — are exactly the same if you were treating a child with asthmatic childhood pneumonia. “You treat the source — this is the pneumonia part — with antibiotics. You treat the symptoms with cough syrup — you don’t ask the child to cough for the next month, until the pneumonia resolves. And you treat the immune system with the inhaled steroid, the Singulair, and all the rest.”

While these treatment recommendations are endorsed by a broad consortium of experts in the PANDAS Physicians Network, they are not accepted by the American Academy of Pediatrics (AAP).

Children who’ve had a recurrence of PANDAS are often given antibiotics for an extended period as a form of prevention, or prophylaxis, for recurring strep infections. Strep is so common in the school population that it is now recommended that prophylaxis continue until patients are about 21, Dr Swedo says. “You want to get them through college, boot camp — places where they’re going to have high exposure to things like mono and strep.” Research shows that antibiotic prophylaxis can reduce significantly the number of episodes of PANDAS symptoms a child experiences.

Unfortunately, even the strep prophylaxis won’t prevent all later episodes of PANDAS symptoms because the immune system, once primed, continues to react to other kinds of infections as well, misidentifying the brain as foreign, and generating symptoms.

“But by preventing the strep,” Dr. Swedo notes, “you prevent over three quarters of those episodes, and you get them down to the point where then symptoms can be controlled with traditional antidepressant medications and CBT.”

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. A 2025 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.”