PANDAS and PANS: When an Infection Triggers Sudden Changes in a Child’s Behaviour
- Tracy Tredoux
- Oct 29, 2025
- 7 min read
Updated: Dec 30, 2025
Imagine your healthy, happy child suddenly developing anxiety, tics, OCD, rage, phobias, insomnia, hyperactivity or depression, almost overnight. You may have heard the term PANDAS and wondered what it means. And no, it’s not about the animal. It’s an acronym for Paediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections.
For many families, this confusing and frightening experience is their first encounter with PANDAS or PANS, conditions that link the immune system to the brain.
Although symptoms were being reported long before, the condition began to gain proper recognition in the medical literature around 2016, when researchers started identifying how certain infections, especially Group A Streptococcus, can trigger dramatic changes in a child’s behaviour, emotions, and motor control.
However, these conditions are still not widely understood in conventional medicine, leaving many children misdiagnosed with psychiatric disorders and placed on medications that often make things worse.
This article will help you understand what’s really going on, how to test for it, and where functional and integrative medicine can play a vital role in recovery.
What Are PANDAS and PANS?
PANDAS stands for Paediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections. It occurs when a child’s immune system reacts abnormally to a strep infection, such as strep throat or scarlet fever.
PANS (Paediatric Acute-Onset Neuropsychiatric Syndrome) describes a similar autoimmune process, but it can be triggered by other infections or immune stressors, such as:
Mycoplasma pneumoniae
Influenza (flu) or other viruses
Lyme disease
Epstein–Barr virus (glandular fever)
Environmental toxins or even severe psychological stress
What Actually Happens in the Body
When a child contracts an infection, the immune system produces antibodies to fight it. This is a normal, healthy response. However, in some children, these antibodies cross into the brain, even though the infection itself is not in the brain. Once in the brain, and through a process called molecular mimicry, the antibodies confuse certain brain cells for the infection, attacking them as if they were bacteria or viruses.
The areas most affected are usually in the basal ganglia, the brain region involved in behaviour, emotions, and movement. The result: a sudden, dramatic change in mood, behaviour, or motor control.
It’s important to understand that the infection may have already resolved, yet the antibodies can linger for months or even years, continuing to disrupt brain function long after the original illness.
Symptoms Parents Often Notice
The onset is typically sudden and extreme. A child who was fine one week may change completely the next. Symptoms can include:
Severe anxiety or panic attacks
Obsessive-compulsive behaviours (OCD)
Tics or involuntary movements
Depression and mood swings
Episodes of rage or aggression
Hyperactivity or attention problems
Insomnia or disrupted sleep
New phobias or fears
Separation anxiety or school refusal
Sudden regression in handwriting, speech, or learning
These symptoms often flare with new infections and may improve temporarily after antibiotics or anti-inflammatories, a clue that the immune system, not the mind, is at the root.
NB! Why PANDAS Can Appear After the Infection Is Gone
When a child contracts a Group A strep infection (like strep throat or scarlet fever), the immune system produces antibodies to attack the bacteria. Normally, once the infection clears, antibody levels gradually fall, and the immune response quietens.
However, in susceptible children, something goes wrong in this “switching off” process.
The Mechanism
The immune system has produced antibodies designed to recognise proteins on the Streptococcus bacteria.
Unfortunately, some of those bacterial proteins look similar to proteins in the brain, particularly in the basal ganglia (a region involved in mood, movement, and behaviour).
Through molecular mimicry, the antibodies mistakenly target those brain cells as if they were bacteria.
The infection is no longer active, but the antibodies linger, continuing to trigger inflammation in the brain and disrupting normal signalling.
This is why a child may seem to “recover” from their sore throat, only to develop sudden behavioural changes days, weeks, or even a couple of months later.
How Long After Infection Can It Start?
The first episode often appears 1-6 weeks after a strep infection.
In some children, it can be several months later if antibody levels remain elevated or if the immune system becomes reactivated by another infection, stress, or environmental toxin.
Once sensitised, future infections (even viral) can retrigger symptoms, as the immune system becomes more reactive over time.
What This Means for Diagnosis
Because symptoms can appear after the infection has cleared, PANDAS can be easily missed if a throat swab is done too late (and shows negative). This is where antibody testing becomes crucial:
ASO (Anti-Streptolysin O) and Anti-DNase B titres can stay elevated for weeks or months, showing that the immune system recently fought strep.
Cyrex or Cunningham Panel testing can reveal ongoing autoimmune activity against brain receptors, even when strep itself is gone.
These results help confirm that the child’s current symptoms are post-infectious, not psychiatric in origin.
How PANDAS and PANS Are Diagnosed
PANDAS/PANS remain predominantly clinical diagnoses, meaning they’re based on history and symptoms. However, modern medicine now uses specific tests to support and confirm the diagnosis.
Conventional Medical Tests
Throat swab or culture: Detects current Group A Streptococcus infection.
ASO (Anti-Streptolysin O) titre: Measures antibodies against strep; rising levels over time suggest a recent infection.
Anti–DNase B antibody: Another marker of recent strep infection, especially if the infection was in the skin or sinuses rather than the throat.
Inflammatory markers: ESR and CRP can indicate ongoing inflammation.
Cunningham Panel: Measures antibodies that target dopamine and lysoganglioside receptors in the brain, and CaM kinase II activity. Elevated levels support the diagnosis of autoimmune involvement in the brain.
Functional and Integrative Testing
Functional medicine looks beyond the infection to understand why the immune system misfired and how to bring it back into balance.
Testing may include:
ASO and Anti–DNase B titres to assess immune activation.
Cyrex Laboratories panels, which measure neural and autoimmune antibodies, helping identify if the immune system is attacking brain tissue or cross-reactive targets.
Comprehensive stool testing to evaluate gut health, inflammation, and the microbiome, as gut dysbiosis often fuels immune dysregulation.
Nutrient status panels (Vitamin D, zinc, selenium, magnesium, omega-3).
Mycotoxin or environmental exposure testing if symptoms persist despite infection resolution.
Conventional Treatment
Typical medical management aims to:
Eliminate any residual infection (usually with antibiotics).
Reduce inflammation and autoimmune activity, using short courses of anti-inflammatory drugs or corticosteroids.
Calm the immune system in severe cases with IVIG (intravenous immunoglobulin) or plasmapheresis.
Address behavioural symptoms with therapy such as CBT (Cognitive Behavioural Therapy) or ERP (Exposure and Response Prevention).
While these treatments can be effective, they often focus on symptom control rather than long-term immune balance.
Functional Medicine Approach
A functional perspective complements conventional treatment by restoring immune regulation, gut integrity, and brain resilience.This involves:
Anti-inflammatory nutrition: omega-3-rich fish, colourful vegetables, turmeric, olive oil, berries, green tea.
Gut-healing support: probiotic and prebiotic foods, reducing processed sugar and refined carbs.
Immune-nourishing nutrients: Vitamin D, zinc, selenium, magnesium, B vitamins.
Detoxification support: hydration, fibre, cruciferous vegetables, gentle sweating (if tolerated).
Stress and sleep optimisation: restorative sleep routines, calming nutrients like magnesium glycinate, gentle breathing exercises, and family support.
Why Awareness Matters
Sadly, many children with PANDAS or PANS are misdiagnosed with psychiatric disorders such as OCD, ADHD, or anxiety and prescribed psychiatric medications that do not address the root cause. Because the problem originates in the immune system, these medications often worsen symptoms or cause side effects without resolving the underlying inflammation. With proper recognition and a targeted approach combining infection control, immune support, gut health, and emotional care, children can and do recover.
In Summary
PANDAS/PANS are autoimmune brain inflammation syndromes, triggered by infections such as strep.
The immune system’s antibodies, through molecular mimicry, mistakenly attack the brain.
Symptoms may include anxiety, depression, rage, OCD, tics, hyperactivity, insomnia, and phobias.
Antibodies can persist long after the infection clears, prolonging symptoms.
Testing includes ASO and Anti–DNase B titres, Cunningham Panel, and Cyrex antibody testing for functional insight.
Integrative treatment focuses on calming inflammation, restoring immune balance, and supporting the brain–gut connection.
A Final Word
If your child’s behaviour changed suddenly after an infection, don’t assume it’s “just anxiety” or “a phase. “Ask about PANDAS/PANS, request immune and antibody testing, and explore an integrative care plan that treats the body and the brain together.
Recovery is possible, and awareness is the first step.
My Personal Experience with PANDAS
I didn’t know it then, but my childhood struggle after Scarlet Fever was my first encounter with what I would later learn was PANDAS.
When I was about seven years old, I became ill with Scarlet Fever, a common childhood infection caused by Group A Streptococcus. I recovered after a couple of weeks, but not long after, something strange happened. One night, I woke suddenly with the terrifying feeling that I couldn’t swallow. From that moment on, I developed a phobia of swallowing that lasted nearly two years.
Mealtimes became distressing for everyone. My parents were worried and frustrated, and I felt frightened and misunderstood. Doctors had no answers. Eventually, this strange fear of swallowing disappeared as suddenly as it had begun, but the memory stayed with me.
Many years later, in 2016, I attended a lecture on PANDAS. As I listened, I felt a jolt of recognition. PANDAS occurs when the immune system reacts to a Strep infection, producing antibodies that mistakenly target the brain, leading to sudden-onset behavioural or emotional changes.
I began researching whether Scarlet Fever could trigger PANDAS and found that it often does. For the first time, I had an explanation for what had puzzled me for decades. What had seemed like “naughty” behaviour was actually an immune-related reaction affecting my brain.
Understanding this connection deepened my compassion for children experiencing similar unexplained struggles and strengthened my belief in looking for root causes, not just surface symptoms.
If you want to have a more personalised discussion about your child's health, book a free discovery call with me today.
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