When children develop JIA, they and their parents can often remember them falling or hurting the joint in some way. However young children fall over and hurt themselves quite often and there is no evidence that arthritis is initiated by injury. People with arthritis often find that they experience more from pain and stiffness in cold, damp weather and we know that rapid change in temperature (both up and down) can precipitate symptoms, but there is no evidence that climate itself is a cause of arthritis. Nor is there evidence that eating particular foods causes arthritis.
Arthritis may be difficult to detect in a young child. Often children do not complain specifically of pain but just seem unhappy or grizzly and off their food. Swelling of a joint may be difficult to detect in a plump toddler. A limp or reluctance to walk or to use both hands normally when playing may be the first sign of arthritis. When a joint is inflamed, the most comfortable position is for the joint to be bent and, if it is not regularly straightened, it may get stuck in this position. Stiffness first thing in the morning is a common feature, meaning that an affected child might find it difficult to climb out of bed or get downstairs first thing in the morning but may be able to move relatively normally later in the day.