Growing Pains or Lyme Disease? How to Tell the Difference
Growing pains or Lyme disease is a common question when children develop leg or joint pain. A nine-year-old complains of knee pain at bedtime. A twelve-year-old wakes up crying with leg aches. A teenager limps after soccer practice. When children report pain, “growing pains” is often assumed—sometimes delaying the diagnosis of Lyme disease.
When “growing pains” is wrong, children can go months without the right diagnosis.
Understanding the difference between growing pains and Lyme disease can prevent months of missed diagnosis while a treatable infection continues to affect joints and function.
For a full overview of symptom patterns, see our
Lyme Disease Symptoms Guide.
For a broader discussion of why Lyme disease is frequently overlooked in children, see
Pediatric Lyme Disease: Why Children Are Often Misdiagnosed.
Growing Pains or Lyme Disease: What Parents Should Know
Both conditions can cause leg discomfort during active growth years and may worsen after activity. These similarities lead clinicians to attribute joint pain to growing pains when Lyme disease is the underlying cause.
However, growing pains are a diagnosis of exclusion. When Lyme disease is present, labeling symptoms as growing pains can delay testing and treatment.
The difference lies in timing, pattern, physical findings, and associated symptoms.
Growing Pains vs Lyme Disease: Key Differences
| Feature | Growing Pains | Lyme Disease (Lyme Arthritis) |
|---|---|---|
| Timing | Night only | Day and night |
| Location | Muscles | Joints (especially knee) |
| Swelling | Never | Common |
| Limping | No | Often present |
| Duration | Minutes to hours | Days to weeks |
| Activity impact | Normal during day | Reduced activity |
When Growing Pains Aren’t Growing Pains
True growing pains occur in muscle tissue, appear only at night, and resolve completely by morning. Children remain active and symptom-free during the day.
Growing pains never cause:
- Joint swelling
- Limping
- Fever
- Limited movement
Red flags that suggest Lyme disease or another condition:
- Visible swelling of knees or joints
- Persistent pain lasting days or weeks
- Daytime symptoms
- Limping or refusal to walk
- Joint-based pain rather than muscle pain
- Migratory pain between joints
- Fatigue, headaches, or rash
- Tick exposure or outdoor risk
Even one red flag warrants further evaluation.
How Lyme Arthritis Presents in Children
Lyme arthritis most commonly affects large joints—especially the knee.
Children may develop:
- Visible joint swelling
- Warmth and stiffness
- Reduced range of motion
- Limping or avoidance of activity
Symptoms may persist for days to weeks and can move between joints over time.
Importantly, Lyme arthritis often appears months after the initial tick exposure, when early signs such as rash or fever are no longer present. Many children do not recall a tick bite.
The Diagnostic Challenge
Growing pains require no testing. This can lead to reassurance without evaluation when children present with leg pain.
In contrast, Lyme disease requires clinical suspicion and appropriate testing.
Children with Lyme arthritis often test positive because symptoms appear later, after antibody development.
Clinical insight: A child with persistent knee swelling after summer outdoor activity should be evaluated for Lyme disease—even if symptoms were initially labeled as growing pains.
For more on testing limitations, see:
Lyme Test Accuracy
Why This Distinction Matters
Growing pains resolve on their own and require reassurance.
Lyme disease requires treatment. Without antibiotics, inflammation may persist and lead to prolonged symptoms or joint damage.
The label “growing pains” can delay diagnosis—sometimes for months—while symptoms continue.
Early recognition changes outcomes.
Frequently Asked Questions
How can I tell if my child has growing pains or Lyme disease?
Can Lyme disease cause leg pain at night?
What does Lyme arthritis look like in children?
Do growing pains cause knee swelling?
Can a child have both growing pains and Lyme disease?
Related Reading
- Pediatric Lyme Disease
- Knee Swelling in Lyme Disease
- MRI and Lyme Arthritis
- ADHD vs Lyme in Children
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
