Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Get emergency help for difficulty breathing, severe confusion, fainting, unusual bleeding, a seizure, or a rapidly worsening illness.
Persistent high fever with marked drowsiness, bruising, or severe weakness also needs emergency assessment because it may signal a serious infection or macrophage activation syndrome.
Contact the rheumatology or eye team promptly for a red or painful eye, light sensitivity, blurred vision, or a new change in vision.
Do not wait for the next routine screening appointment.
Seek urgent medical advice for a high fever in a child taking immune-suppressing treatment, especially if they appear unusually unwell.
The treating service may have specific instructions about fever, infection, and whether a medicine should be delayed.
Arrange a routine medical assessment for joint swelling, morning stiffness, an unexplained limp, or reduced joint movement that persists or keeps returning.
A child with known JIA should also be reviewed if pain or stiffness is increasing, daily activities are becoming harder, or treatment side effects are suspected.
Every sign above is quoted from the sofidex article on Juvenile idiopathic arthritis. If you are not sure, err upward — it is always reasonable to be checked.