The five-year-old who wakes crying at 10pm with aching legs, who is fine by morning and entirely normal the next day, is a very familiar presentation to paediatric GPs. Growing pains are extremely common, affecting somewhere between a quarter and a third of children in the primary school years and sometimes starting as early as three.
The name is misleading in one important respect: the pain is not actually caused by growth itself. Bones do not hurt as they grow. The mechanism behind what is called growing pains is not fully understood, which is unsatisfying but true. What is clear is that the pattern of symptoms is consistent and recognisable, the condition is benign, and parents knowing what it is and what it is not makes night-time episodes considerably less frightening.
Healthbooq (healthbooq.com) covers common childhood health conditions in the early years, helping parents understand symptoms and know when to seek advice.
What Growing Pains Feel Like
The classic pattern is intermittent pain in the legs, usually the muscles of the thighs, shins, or calves, rather than in the joints. It comes on in the late afternoon or evening, often waking the child from sleep. It tends to affect both legs, though one may be worse than the other on a given night. By morning, the child is usually completely pain-free and shows no sign of difficulty walking or stiffness.
The pain can be genuinely distressing at the time. Some children cry with it. Rubbing the legs, gentle massage, and warmth (a warm pack or hot water bottle wrapped in a towel) tend to give relief. Paracetamol or ibuprofen at appropriate doses also help.
The episodes are intermittent. A child might have them several nights in a row, then not for weeks, then again. They do not follow a predictable schedule.
The child is otherwise well. No fever, no joint swelling, no redness, no limp.
What Causes Growing Pains
There is no definitive answer. Several hypotheses have been proposed over the years.
Bone-to-muscle proportion theory suggests that during periods of rapid growth, the bones grow faster than the muscles attached to them, creating tension in the muscles that generates pain. This has a certain intuitive logic but direct evidence for it is limited.
Activity-related muscle fatigue is another possibility: children who are very physically active during the day may experience delayed muscle soreness that presents in the evening. There is some observational support for this, with pain being more common on days of high physical activity.
Lower pain threshold in affected children has also been suggested, as children who have growing pains also tend to be more sensitive to pain in other contexts.
The honest answer is that the pathophysiology is not well established, which is why "growing pains" remains a descriptive term rather than a mechanistic diagnosis.
Distinguishing from Concerning Causes of Leg Pain
Growing pains are a diagnosis of exclusion: other causes of leg pain need to be considered and, where there is doubt, assessed.
The features that distinguish growing pains from more serious causes are the bilateral nature (both legs), the location in muscles rather than joints, the presence exclusively at night with complete resolution by morning, and the absence of any other symptoms.
Pain that should prompt medical assessment includes: pain in a single leg only, pain in a joint rather than a muscle, pain that is present during the day as well as at night, pain associated with a limp, swelling, warmth, or redness around a joint, pain accompanied by fever, pain that wakes the child and does not settle with simple analgesia and massage, and pain that has changed in character or is getting progressively worse.
Conditions to consider in the differential include: juvenile idiopathic arthritis (joint inflammation, usually causing stiffness worse in the morning, not at night), transient synovitis (a self-limiting hip inflammation usually after a viral infection, causing a sudden limp), Perthes disease (disruption of blood supply to the femoral head, causing limp and hip pain), leukaemia (bone pain from marrow infiltration, usually accompanied by other features like pallor, bruising, or fatigue), and stress fractures in very active children.
A child who is limping needs to be assessed. Full resolution every morning and a normal examination are the reassuring features of growing pains.
Management
There is no treatment that prevents growing pains. Management is symptomatic.
Massage is the most consistently effective immediate relief measure. Rubbing the calf or thigh firmly seems to reduce the pain, possibly by competing with pain signals at the spinal cord level (the gate control mechanism of pain modulation).
Warmth applied to the painful area gives relief in many children. A covered hot water bottle or warmed wheat bag is suitable. It should not be hot enough to burn.
Paracetamol or ibuprofen (at appropriate doses for the child's weight) can be given during painful episodes. Some families find that giving a dose early in the evening on days of high activity helps prevent episodes that would otherwise wake the child.
Stretching exercises, particularly calf and hamstring stretches done before bed, are sometimes suggested and some children find them helpful, though the evidence base is limited.
Key Takeaways
Growing pains are a common and benign condition causing intermittent aching pain in the legs of young children, typically at night and in both legs. They affect around 25 to 40 per cent of children. Despite the name, the pain is not caused by the process of physical growth, and the exact mechanism remains uncertain. The diagnosis is clinical and made by exclusion of more serious causes. Pain that is present in the daytime, is in one leg only, is associated with swelling, redness, or fever, or that limits the child's walking warrants medical assessment.
