They’re plenty confusing to parents – these mysterious pains that plague kids’ legs at night and reliably vanish by morning. Medical tests show that there’s nothing wrong, and your child’s doctor has no tips on preventing or treating the pain.
“Growing pains” are a common childhood ailment. And yet, they’re not even caused by a child’s growth.
“It is true that muscles, tendons, ligaments and bones grow continuously, but the growing process alone seldom causes pain,” explains Francis Y. Lee, M.D., an orthopedic surgeon at Children’s Hospital of New York and Columbia University.
In fact, growing pains are most common from ages 3 to 12, when kids aren’t having rapid growth spurts. So why call them “growing pains”? Because all children eventually outgrow them, says William Oppenheim, M.D., a pediatric orthopedic surgeon with the Luskin Children’s Clinic of Los Angeles Orthopaedic Hospital and the UCLA Department of Orthopedics.
What They Are
Growing pains are the third most common type of pain in children ages 3 to 12 (headache and stomachache rank first and second), impacting between 15 percent and 30 percent of this age group.
The pains tend to occur:
- at night,
- for a few nights at a time, every one to three months,
- in both legs, and
- in the thighs, calves and behind the knee.
In the morning, kids who had been suffering from growing pains get around just fine; you’d never know they had a problem. “During the day they’re totally normal,” says Meghan Imrie, M.D., associate clinical professor of orthopedic surgery at Stanford University. Any lab tests that your pediatrician performs will also come back normal if growing pains are the problem.
What They Aren’t
The most important thing to know about growing pains is that this is a “diagnosis of exclusion,” Imrie says. That means growing pains are diagnosed after doctors rule out everything else.
Here are some symptoms that do not indicate growing pains and should be reported to your child’s doctor:
- pain that is focused in one spot or one leg only (localized)
- pain focused in the joints, making a child feel “stiff” in the mornings
- pain that’s persistent, rather than coming and going in spates
- pain accompanied by fever, swelling or tenderness
- pain with injury or bruising
- pain that causes a child to limp during the day, or curtail his physical activities.
Similar to growing pains is a condition called transient synovitis. Its cause is also unknown, but this condition brings day and nighttime joint pain in the knee or hip. Kids with transient synovitis don’t have fever or other signs of infection, but the pain may become so severe that they walk with a limp. The condition usually clears after three or four days, with no long-term effects.
Painful joints with swelling and fever, on the other hand, are a big red flag, and you should have your child seen by a doctor immediately. This can be a sign of joint infection, which Oppenheim warns can cause permanent damage within a day or two.
A hopeful sign, believe it or not, is if your child’s pain stays the same. “More worrisome things like a tumor or arthritis become worse over time,” says Imrie. Those are two of the serious conditions connected with nighttime leg pain in kids. Others include leukemia (cancer of the white blood cells) and lymphoma (cancer of the lymphatic system).
Less-serious causes of leg pain include injury or overuse of muscles (strains), ligaments (sprains), bones (stress fracture) and joints (cartilage bruise). Long-distance runners can develop pain in the thigh, which may indicate a stress fracture. Basketball players can have pain over the front of the knee, a condition called Osgood-Schlatter’s disease (apophysitis). But these things usually get better when physical activity is reduced, explains Lee.
No one knows what causes growing pains, “and that makes it a bit of a problem,” says Oppenheim. Especially frustrating since the condition was first described in 1823! He points to a Journal of Foot and Ankle Research article from 2008 that shows that research on the topic has been plentiful, but “lacking in scientific rigor.” Still, there have been plenty of theories about the cause of growing pains:
- Muscle fatigue – This theory hasn’t been tested, but parents of kids with growing pains often report that they’re linked to increased physical activity.
- Bone fatigue – Studies have shown that the bones of kids with growing pains are less dense (and so weaker) than those of other children, leading some to suspect the pain comes from bone fatigue.
- Genetics – Experts suspect that low pain thresholds run in families, and some studies show that kids with growing pains have lower pain thresholds than their peers without.
- Joint hypermobility – Another untested theory is that children with growing pains are “double jointed,” a trait also common to children with painful conditions such as fibromyalgia.
Oppenheim’s personal theory is that because children in this age range are so physically active, they make the periosteum (a membrane containing blood vessels and nerves that covers the bones) sore. It’s much thicker in kids than in adults, and could be less flexible. But Oppenheim says he doesn’t have research to back this up. “Nothing has really been pinned down,” he says.
What You Can Do
There aren’t any proven treatments for growing pains, in part because it’s difficult to prove whether a given treatment worked or whether the child just outgrew the condition. Still, some things do seem to help:
- Heat and massage, if that feels good to the child, and
- Over-the-counter pain medications such as Tylenol and Advil.
“It’s basically just rubbing where it hurts, kissing the boo-boo,” says Imrie.
Oppenheim puts it another way. “You can be sympathetic and carry them through it,” he says. “And you can realize it’s not the end of the world, and they will outgrow it.”
• American Academy of Orthopaedic Surgeons – orthoinfo.aaos.org/menus/children.cfm – Information on all sorts of conditions that affect kids’ bones and joints.
• The Arthritis Foundation’s JA Alliance – arthritis.org/ja-alliance-main.php –The lowdown on juvenile arthritis.
• Alliance for Youth Sports Safety – youthsportssafetyalliance.org – An organization dedicated to sports safety, sponsored by major players like the American Academy of Pediatrics and the National Athletic Trainers’ Association.