For many kids, growing pains are as common as skinned knees and runny noses. Twenty-five to 40 percent of children are bothered by these aches, which experts believe aren’t caused by lengthening limbs at all, but rather from running, jumping and playing hard all day. 

For some children, though, aching limbs can be a symptom of something considerably more sinister than muscle soreness. According to the Arthritis Foundation, nearly 300,000 kids under age 16 suffer from juvenile arthritis (JA), which the organization says is an umbrella term for the “many autoimmune and inflammatory conditions or pediatric rheumatic diseases that can develop in children.”

Children with JA can suffer from the same kind of joint stiffness and pain as do adults with arthritis, but kids can’t always vocalize what they’re feeling. That’s one reason parents may mistake complaints about body aches for so-called growing pains and wait to get help.

In fact, says Jaya Srinivasan-Mehta, MD, chief of pediatric rheumatology at St. Joseph’s Children’s Hospital in Paterson, New Jersey, “kids often are brought to a doctor because of a change in behavior or activity rather than the child vocalizing complaints of joint pain.”

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“Mom, it hurts!” — when to worry

Arthritis in a child not only damages bones and joints, it also can affect growth plates in bones that are still developing. This means bone growth may be stunted or uneven. For that reason, the sooner JA is diagnosed and treated, the better for a young child.

And in fact, it’s not hard to distinguish so-called growing pains from pain due to JA. The symptoms differ in several significant ways.

Location. Growing pains typically cause a throbbing ache in the fronts of a child’s thighs, her calves or behind her knees, according to the Mayo Clinic. Pain from JA will affect joints more directly and aren't limited to the legs. The National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) says JA also can involve hands and feet.

Timing. Kids experience growing pains only at night, say experts at the Hospital for Special Surgery in New York City. Sometimes their legs ache so much it wakes them up, but they always feel better in the morning. When a child still has pain in the morning or says he’s hurting during the day, though, he could have JA.

Other symptoms. The type of ache caused by growing pains usually feels better after 10 or 15 minutes of gentle massage. Arthritis pain in kids is more persistent. Joints also may be red, swollen and warm or hot to the touch. “Stiffness in the morning or difficulty performing regular daily activities also should raise concern,” adds Srinivasan-Mehta. Other symptoms can include high fever, skin rash and swollen lymph nodes, the NIAMS adds.

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Rx for growing pains

If you’re worried your child has symptoms of juvenile arthritis, take him to be evaluated by a pediatric rheumatologist right away. "Because pediatric rheumatic diseases each have their own set of symptoms, it’s important a thorough evaluation is done to determine the appropriate diagnosis,” explains Srinivasan-Mehta. These conditions also are treated differently than similar ones in adults.

But if you suspect that your kid’s pains are merely muscle soreness after a hard day on the playground or sports field, you can ease the ache with massage, a heating pad, an age-appropriate dose of ibuprofen, gentle stretching and, of course, some TLC.

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Katherine Oakes is a health and lifestyle writer and dedicated hatha yoga instructor. She strives to live an inspired, conscious life and enjoys homemade guacamole.