What are the reasons for joint pain in children with multiple joints?

Patient's question:

Main symptoms: Pain in both knee joints with slight redness and swelling
Onset time: Test results: X-ray showed no apparent abnormalities

Doctor's answer:

Many parents have experienced this: children often complain of joint pain during certain periods. Parents often assume their child has arthritis. However, there are many causes of joint pain, and true arthritis has its own distinguishing features. Parents should not jump to conclusions. When a child has joint pain, it's important to check if the joints are swollen. If there is no swelling, it cannot be diagnosed as arthritis. If swelling does occur, it's necessary to see a doctor, especially if multiple joints are swollen.
Besides arthritis, growing pains are also a cause of joint pain. So, how can parents determine if their child is experiencing growing pains? Growing pains typically occur when a child is between five or six years old, or seven or eight years old. The pain usually happens at night, with no discomfort during the day. Some children may even wake up parents by kicking their legs, but the pain disappears by the next morning. The exact cause of growing pains is still unclear. However, if parents suspect their child has growing pains, no special treatment is needed. This condition usually resolves as the child grows older.
Additionally, loose ligaments can also cause joint pain. What are loose ligaments? Hands and legs are very flexible, with hands often bending to the level of the arms. Legs are not straight and may bend backward. Some parents mistake this for (cartilage disease), but it is actually loose ligaments, which are somewhat related to genetics. For such children, it's important to strengthen their ligaments through exercises like cycling, running, and jumping rope.
The treatment for growing pains in children primarily involves rest. After school, if a child feels discomfort in the knees or calves, they should not be forced to do more exercise. Before bed each night, warm water can be used to soak the child's feet and calves. However, when the child is not tired, they should be encouraged to move more to strengthen muscles and promote natural correction of tibial deformities.
If the pain is severe, local massage, pain relievers, or a moderate intake of vitamin C may be used. With proper rest, exercise, massage, and symptomatic medication, growing pains in children will heal quickly without leaving any aftereffects or affecting normal growth and development.