Idiopathic Limb Pain of Childhood
Night-time leg pain that worries parents — here's what you need to know
Growing pains are a common cause of leg pain in children aged 3–12. There is no strict medical definition of the term — "growing pains" is a diagnosis of exclusion, made only after other conditions have been ruled out. They cause deep, aching pain — typically in the thighs, calves, or behind the knees — that appears at night and resolves by morning. Despite the name, growing pains are not caused by bone growth itself. The exact cause remains unknown, though muscle fatigue and low pain threshold are thought to contribute.
Running, jumping, and active play create accumulated muscle fatigue
Leg muscles become fatigued but pain is suppressed during activity due to high adrenaline
When the child lies still and rests, accumulated muscle tension is perceived as pain
After rest, the muscles recover and children feel completely normal the next day
Once other conditions have been ruled out, growing pains usually ease as the child grows, and most children outgrow them by puberty. No specific treatment is required — only comfort measures. However, if pain is persistent, asymmetric, or associated with swelling or fever, a medical evaluation is needed to rule out other causes.
When to see a doctor: Growing pains should be diagnosed by exclusion. Red flags requiring evaluation include: fever, a swollen joint that feels hot, pain severe enough that the child cannot walk or bear weight, daytime pain, limping, or pain in only one leg. These may indicate septic arthritis or osteomyelitis, which need urgent treatment, or juvenile idiopathic arthritis, a bone tumour, or leukaemia. If night pain comes with pallor, easy bruising, weight loss, a persistent low-grade fever, or low energy, blood tests are needed. Limping can also point to transient synovitis, Perthes disease, or slipped capital femoral epiphysis.