PANS is diagnosed using the following criteria:

Sudden & acute onset of OCD or severely restricted food intake.
Concurrent severe & abrupt onset of symptoms from at least 2 of the neuropsychiatric categories below:
- Anxiety, Separation Anxiety
- Emotional Lability, Depression
- Aggression, Irritability, Oppositional Behavior
- Behavioral/Developmental Regresion
- Deterioration of learning abilities related to ADHD
- Sensory & Motor Abnormalities
- Somatic Signs: sleep disturbances, enuresis, urinary frequency
- Symptoms not better explained by a known medical or neurological disorder. It is a "diagnosis of exclusion".
There is no age requirement, typically symptoms start during grade school but post-pubertal cases are not excluded.

Additional Notes on PANS:

Can have Motor & Phonic tics (whooping, wringing hands)
Can have episodes of extreme anxiety or aggression.
Can have visual or auditory hallucinations identical to the psychotic symptoms seen in conditions such as schizophrenia, bipolar disorder, and lupus cerebritis.
Can have a decline in handwriting & math skills.

PANDAS is diagnosed using the following criteria:

Significant OCD and/or debilitating/incapacitating Tic symptoms
Pediatric Onset – Symptoms have an evident onset between 3 years of age and puberty but post pubertal onset is possible. Pediatric onset specified as it is time of peak exposure and cross-species immunity of GAS infections.
Acute onset and episodic course: Defined as either a dramatic onset of OCD or tic symptoms or by relapsing-remitting symptoms that erupt with an acute change. Between episodes, symptoms may lesson but not return to pre-syndrome levels.
Associated with Streptococcal-A (GABHS) infection. Note: not all patients will have pharyngitis; strep may be in locations other than throat or patient may be a carrier without active infection. Secondary triggers can be due to exposure to strep or other pathogens.
Neurologic abnormalities (motoric hyperactivity, choreiform movement) during symptom exacerbation

Additional Notes on PANDAS:

In conjunction to OCD and/or tics, patients often concurrently experience the comorbid neuropsychiatric symptoms seen in PANS with the same acute and dramatic onset.