PANS and PANDAS: when your child's behaviour changes suddenly

What PANS and PANDAS actually are

Two closely related clinical pictures, both involving a sudden onset of neuropsychiatric symptoms in a previously well child, usually following an infection.

PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections) was described by Susan Swedo and colleagues at the US National Institute of Mental Health in 1998. The hypothesis is that group A streptococcal infections (the bug that causes strep throat and scarlet fever) trigger an autoimmune response that affects the basal ganglia of the brain, producing sudden obsessive-compulsive symptoms or tics in a previously well child.

PANS (Pediatric Acute-onset Neuropsychiatric Syndrome) is the broader category. It includes PANDAS but also covers similar acute-onset pictures triggered by other infections (mycoplasma, viruses, Lyme disease in some accounts) or by other immune events. The American Academy of Pediatrics published a clinical report in March 2024 summarising the current understanding. (AAP, 2024. See References.)

The core diagnostic features (from the original criteria):

• Abrupt onset. Days, not months. The child who was fine on Saturday is unrecognisable by Friday.
• OCD or severely restricted food intake as the lead symptom in PANS; OCD or tics in PANDAS.
• At least two of: anxiety, emotional lability, irritability/aggression, behavioural regression, decline in school performance, sensory or motor changes, sleep disturbance, urinary symptoms.
• For PANDAS specifically: evidence of recent streptococcal infection.

The recognisable pattern: the sudden onset

The thing that makes PANS and PANDAS distinctive is the speed of the change.

Parents describing the onset reliably use the phrase “overnight.” The classic pattern is:

1. A previously well, settled, age-typical child has an infection (often a sore throat, but sometimes a chest or viral infection).
2. Days to weeks after the infection, the child changes. Suddenly. Inside a fortnight, sometimes inside 72 hours.
3. The change is dramatic and recognisable to family. The child is “not themselves.” OCD-like rituals, tics, intense separation anxiety, regression in toileting or speech, refusal to eat, sleep collapse, personality change.
4. Sometimes there is a partial improvement, then a relapse after the next infection.

What else could explain a sudden behaviour change

A sudden change in a previously well child is always worth a full medical workup. The clinician will rule out several things alongside or before PANS/PANDAS.

• Encephalitis, including autoimmune encephalitis (e.g., anti-NMDA receptor encephalitis). Some cases present with psychiatric symptoms before neurological signs become obvious. Important to rule out.
• Other autoimmune or inflammatory conditions: Sydenham's chorea, lupus, Hashimoto's.
• Adverse drug reactions, including to common medications.
• Trauma or safeguarding concerns. A sudden change in behaviour in a child can sometimes signal abuse; this is a routine part of any clinical assessment.
• Substance use in older children.
• Standard childhood OCD or anxiety that has existed for longer than the family realised and is now visible.
• Other neurological or endocrine conditions.

A sudden onset always warrants paediatric assessment. Don't let the controversy over PANS/PANDAS specifically delay that.

The NHS position in 2026 (honestly)

The territory is contested. Naming that clearly is more useful to you than pretending it isn't.

The state of UK clinical guidance as of early 2026:

• November 2024: NICE concluded there was insufficient evidence to develop a NICE clinical guideline on PANS/PANDAS. NICE acknowledged the conditions exist as clinical descriptions; the decision was that the evidence base for specific diagnostic and treatment guidance was not yet strong enough. (NICE, 2024. House of Commons Library briefing, 2024.)
• April 2024: The Royal College of Paediatrics and Child Health (RCPCH) began work, in partnership with PANS PANDAS UK, to develop RCPCH-accredited UK clinical guidelines for PANS and PANDAS. This work is ongoing.
• NHS Tayside and a small number of other UK services have published local PANS/PANDAS reference materials; coverage is patchy.
• House of Commons Library briefing (2024) summarises the state of the debate accessibly for parents.

What this means in practice: your local GP and paediatrician may have a wide range of views, and the care you get can depend on whether your clinician has been to a PANS PANDAS UK training event. Some NHS clinicians will assess, investigate and treat. Some will refuse to acknowledge the diagnosis. PANS PANDAS UK maintains a list of UK clinicians known to have experience.

The UK pathway as it currently runs

There is no national pathway. There is a workable pathway most families end up on.

1. GP first. Describe the picture: sudden onset, the preceding illness, the specific OCD or tic symptoms. Ask for a throat swab and ASO titre (antistrep- tolysin O antibodies, a blood test that can show recent strep). Ask for a paediatric referral.
2. Paediatrician. A general paediatrician should assess for the differential conditions named above. Some will know about PANS/PANDAS; some will not. If they are dismissive, ask whether they have read the RCPCH guideline development materials or the AAP 2024 clinical report.
3. Specialist referral if needed. Some UK paediatric neurologists and immunologists with PANS experience are listed by PANS PANDAS UK. A small number of NHS centres see complex cases. Where NHS routes are closed, families sometimes seek private paediatric immunology or neurology assessment; this is a real financial and access decision.
4. CAMHS in parallel for the psychiatric symptoms (OCD, anxiety, tics). NICE-recommended CBT with ERP is appropriate regardless of whether PANS/PANDAS is confirmed.
5. Treatment, where indicated. Where PANS or PANDAS is confirmed, the standard approach in experienced clinics includes treating any active infection (antibiotics for strep), and considering anti-inflammatory or immunomodulatory treatments. The specifics are specialist-led; this article does not recommend a treatment.

What you can do while you push for clarity

The assessment process is slow. Several things help in the meantime.

1. Document everything. A simple notebook or phone notes file. Daily entries. Symptoms, severity, triggers, sleep, eating, medication. Two or three short video clips of the new symptoms (with your child's knowledge where appropriate). This is your single biggest asset.
2. Address the OCD/tics symptoms directly. Standard evidence-based approaches (see our articles on OCD in primary-age children and Tourette's) help regardless of whether PANS/PANDAS is confirmed.
3. Look after the family. The sudden change is traumatic for siblings and parents too. Keep the structures of family life as predictable as possible.
4. Join PANS PANDAS UK. Free. UK-specific forums, helpline, clinician lists, and templates for the harder conversations with NHS services.
5. Don't leave the school in the dark. Brief the SENDCO with a short written summary. Request reasonable adjustments under the Equality Act 2010 while the picture is being worked through.

The FII accusation risk and how to protect against it

A small number of UK families seeking PANS/PANDAS assessment have faced Fabricated or Induced Illness (FII) accusations. PANS PANDAS UK published a 2024 report on this directly.

FII is a recognised form of medical child abuse where a caregiver fabricates or induces illness in a child. It is taken very seriously by safeguarding teams. The intersection with contested diagnoses is that some clinicians, on encountering an unfamiliar diagnostic concept, have wrongly attributed parents' persistence in seeking answers to FII rather than to advocacy for a child with a real and unrecognised illness. PANS PANDAS UK's 2024 FII report documents specific cases and offers guidance. (PANS PANDAS UK, FII Report 2024. See References.)

What helps protect you, in the unlikely but real event the conversation goes that way:

• Contemporaneous records. Dates, videos, symptom diaries written as they happen.
• Independent observer corroboration. School, the other parent, grandparents, anyone else who saw the change. Their independent accounts matter.
• Stick to the clinical literature. Cite the AAP 2024 report, the RCPCH guideline development, the House of Commons Library briefing. These are mainstream references.
• If safeguarding gets involved, ask for IPSEA-style legal support. For SEND issues IPSEA is the lead. For safeguarding specifically, Family Rights Group (frg. org.uk) is the right call.
• Don't doctor-shop unilaterally. Stay within the NHS pathway where possible. If you go private, keep the GP informed in writing.

When to escalate urgently

Some presentations are genuine medical emergencies.

• Confusion, drowsiness, seizures, loss of consciousness: 999 or A&E. Could be encephalitis.
• Refusal of fluids, signs of dehydration, severe weight loss: A&E or paediatric assessment unit.
• Self-harm or talk of not wanting to be here: GP today, NHS 111 option 2, or A&E.
• Severe, rapid deterioration over hours: A&E.

What to do this week

Three things.

1. Start the diary today. Date, symptoms, sleep, eating, mood. Two short paragraphs a day. Take a video clip of the most visible new behaviour.
2. Make the GP appointment. Take the diary. Ask for a throat swab and ASO titre. Ask for a paediatric referral with the words “acute-onset neuropsychiatric symptoms” in the referral letter.
3. Join PANS PANDAS UK. Free. The information, the helpline, and the clinician list are substantial.