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Doctors haven't been able to pinpoint an exact cause of growing pains, but multiple factors, including physical activity, muscle fatigue or overexertion, may be to blame.
Doctors haven’t been able to pinpoint an exact cause of growing pains, but multiple factors, including physical activity, muscle fatigue or overexertion, may be to blame.
Amy Bentley
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If your child wakes up in the middle of the night with leg pain that can’t be linked to a specific cause or injury, it might be what’s referred to as “growing pains” – even though the pain isn’t related directly to physical growth.

“It’s legitimate, especially in young children from 3 to 6,” said Dr. Michael W. Cater, an Orange County pediatrician with an office in Tustin.

Growing pains generally occur in the legs, and the pain most commonly hits in the middle of the night, waking up the child, Cater says. The pain can be felt in the calves, the back of the thighs or behind the knees, and it’s often gone by morning. It’s usually intermittent, but may recur over several nights, according to Cater.

Doctors haven’t been able to pinpoint an exact cause, but multiple factors, including physical activity, muscle fatigue or overexertion, may be to blame. Experts doubt these pains are connected to actual growth, which happens too slowly for children to feel it – although they do strike children during the growing years, typically from ages 3 to 5 and 8 to 12, according to kidshealth.org, which is funded by the Nemours Foundation Center for Children’s Health Media.

Kidshealth.org estimates that 25 percent to 40 percent of children experience growing pains, and the cause, according to the American Academy of Pediatrics, may be too much muscle exertion during the day.

“Children don’t feel sore while they’re having fun; only later, when the muscles relax, do the pains come on,” according to an article on the AAP’s website.

Dr. Andrew Shulman, a pediatric arthritis specialist and rheumatologist at Children’s Hospital of Orange County, says, “It’s usually something benign.” He explained that there is a “mechanical” cause related to limb use, joint range of motion and joint flexibility, in most cases.

The pain is often related to activity in a young child and can be in muscles, joints or ligaments, Shulman said. A long day walking around Disneyland can be enough to bring it on, for example. “We don’t think the actual physiology of growing itself is painful, but bones might grow faster than ligaments, joints getting more flexible.”

Both Cater and Shulman note numerous medical conditions are associated with leg pain, so it’s important for parents to make sure their child doesn’t have something more serious. If the pain is persistent, carries over into the daytime, is associated with a limp, redness, swelling, tenderness, fever, rash or excessive fatigue or if there was a recent injury, the child should see a pediatrician and a specialist, if needed, Cater and Shulman said.

“A careful history is usually sufficient to make a diagnosis of growing pains. Laboratory tests are generally not indicated for this relatively common childhood complaint.

The outlook for this condition is very positive and, with time, the child will outgrow the discomfort,” Cater says.

“A good history or description of symptoms and a physical exam will pretty much get us to the answer 90 percent of the time,” Shulman says. “The red flag that it’s maybe not mechanical would be the opposite pattern: If the pain is worse in the morning and improves with movement and activity.” Then it could be something like arthritis, he said.

The pain usually responds well to massage, heat and acetaminophen or ibuprofen.

Shulman said kids with growing pains should continue to be active.

“We don’t want to limit their activity. We want to find a way for them to continue their sport or activity of choice. Most of this will improve with growth and muscle strengthening” and a sturdy pair of shoes with good arch support, he said.

The AAP suggests it’s best for kids to participate in a wide variety of physical activities – not just one sport, for instance, so the child uses different muscle groups and isn’t overusing the same muscles, making them sore.