For PANDAS, Group A streptococcus — the bacteria behind strep throat — is the identified trigger. PANS can be set off by a broader range of infections, including Mycoplasma pneumoniae, influenza, sinusitis, and upper respiratory infections. In some children, significant stress may also play a role. Parents who have been through a previous episode often learn to recognize early signs that another may be building — a return of prior behaviors, new sleep problems, increased irritability, urinary frequency, handwriting changes, or food refusal that appears suddenly. These are patterns worth bringing to your provider's attention promptly rather than waiting to see how things develop.