Growing Pains in Children: What They Are, What They're Not, and When to Worry

What Are Growing Pains?

"Growing pains" is one of the most common concerns parents bring up at well-child visits at Hummingbird Pediatrics in Robbinsville, NJ. Your child wakes up crying in the middle of the night, rubbing their legs and saying they hurt — and then by morning, they're running around as if nothing happened. Sound familiar?

Growing pains are real, common, and benign — but the name is a little misleading. They don't actually happen during growth spurts, and we don't fully understand what causes them. What we do know: they affect an estimated 25–40% of children, most commonly between ages 3 and 12, and they almost always resolve on their own as children get older.

What Causes Growing Pains?

Despite the name, growing pains are not caused by bones growing. The exact cause is still debated among pediatric researchers. Current theories include:

Muscle fatigue: Children's muscles may become fatigued from a day of running, jumping, and active play — and the discomfort surfaces at rest when the muscles aren't distracted
Reduced pain threshold: Some children may have a lower sensitivity threshold for normal sensations in their muscles
Restless leg component: There may be some overlap with restless leg syndrome in certain children

Growing pains tend to be worse after unusually active days and may come and go for months to years before resolving completely.

Classic Growing Pain Symptoms

True growing pains have a very consistent pattern. If your child's leg pain matches all of the following characteristics, growing pains are the most likely explanation:

Location: Both legs (bilateral) — typically in the thighs, calves, or behind the knee. Rarely in the joints themselves.
Timing: Almost always in the late afternoon or at night — often waking the child from sleep
Duration: Typically 30 minutes to a few hours
Gone by morning: The child wakes up completely fine and has no pain or limp during the day
No visible changes: The legs look completely normal — no swelling, redness, or warmth
Normal activity: The child plays and runs normally during the day without any problems

Growing Pains vs. Warning Signs — At a Glance

Typical growing pains:

Both legs
Nighttime or late afternoon only
Gone by morning
No swelling, redness, or warmth
Child runs normally during the day
No fever

Warning signs — not growing pains:

One leg only
Daytime pain too
Pain persists in the morning
Swelling, redness, or warmth at the joint
Child limps or refuses to walk
Fever present

What Growing Pains Are NOT

Because the symptoms overlap with several more serious conditions, it's important to know what growing pains should NOT look like. The following conditions can mimic growing pains but require medical evaluation:

Juvenile Idiopathic Arthritis (JIA)

JIA causes joint swelling, stiffness, and pain — especially in the morning (morning stiffness is a hallmark), which is the opposite of growing pains. JIA pain is often in the joints themselves (knees, ankles, wrists) and visible swelling may be present.

Lyme Disease

New Jersey has one of the highest rates of Lyme disease in the country. Lyme arthritis typically causes intermittent pain and swelling in large joints — often the knee — in a child who may have had a tick bite weeks or months earlier. If your child has joint swelling after potential tick exposure, Lyme testing is warranted.

Leukemia and Bone Tumors

Bone pain from leukemia or bone tumors is rare but important not to miss. Red flags include pain that is constant rather than episodic, pain in the bones rather than muscles, nighttime pain that wakes the child every night without relief, and any associated bruising, pallor, or swollen lymph nodes.

Stress Fractures or Overuse Injuries

In active or athletic children, overuse injuries can cause leg pain that feels worse with activity and improves with rest — the opposite of growing pains.

Talk to Your Pediatrician If Your Child Has:

Pain only in one leg
Pain in the joints (not the muscles between joints)
Daytime pain that limits activity or causes limping
Swelling, warmth, or redness around a joint
Pain every single night for more than 2 weeks without any pain-free nights
Fever along with the leg pain
Pain that doesn't improve with massage or pain relief
Any associated bruising, weight loss, or fatigue

Home Management of Growing Pains

When growing pains strike, these simple measures work well for most children:

Massage: Firm, gentle massage of the affected muscles is often the most effective and immediate relief — and children love the comfort of your touch
Heat: A warm (not hot) heating pad or warm towel on the aching muscles for 15–20 minutes can ease discomfort
Stretching: Gentle calf and thigh stretches before bed may reduce the frequency and severity of episodes — ask your pediatrician to demonstrate some simple stretches
Pain relief: An age-appropriate pain reliever can help on nights when pain is more severe; ask your pediatrician which product and dose is appropriate for your child's weight
Comfort and reassurance: Reminding your child that the pain will pass and that their legs are healthy goes a long way — anxiety about pain can amplify it

Reassurance for Parents

It can be hard to watch your child cry in pain in the middle of the night, especially when you're not sure what's causing it. The good news: true growing pains are completely harmless. They don't cause lasting damage, they don't affect development, and virtually all children outgrow them entirely by early adolescence.

If the pain pattern fits growing pains and your child is running around normally during the day, you can manage it at home with confidence. But if anything doesn't fit — or you simply want reassurance — that's exactly what your pediatrician is here for.

At Hummingbird Pediatrics in Robbinsville, NJ, our board-certified pediatricians can help you tell growing pains from something that needs further evaluation. Call us at (609) 808-3123 or book an appointment online — we'll put your mind at ease.