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 joint or muscle pain, “growing pains” becomes the default explanation—delaying investigation of Lyme disease.
Understanding the key differences prevents months of dismissed symptoms while treatable infection damages joints.
For a broader discussion of why Lyme disease is frequently overlooked in children, see Pediatric Lyme Disease: Why Children Are Often Misdiagnosed.
Why Growing Pains and Lyme Disease Get Confused
Both cause leg and joint pain during active growth years and may worsen with activity. These similarities lead pediatricians to dismiss joint pain as growing pains when infection is the actual cause.
Growing pains represent a diagnosis of exclusion—applied when no other cause is found. When Lyme disease produces joint pain, this label prevents testing and treatment.
The critical difference lies in timing, pattern, physical findings, and associated symptoms.
When Growing Pains Aren’t Growing Pains
True growing pains occur in muscle tissue, appear exclusively at night, and resolve completely by morning. Children walk, run, and play normally during the day.
Growing pains never cause limping, swelling, fever, or limitation of movement.
Red flags requiring investigation:
- Visible swelling of knees, ankles, or other joints
- Persistent pain lasting days or weeks
- Daytime symptoms interfering with activities
- Limping or refusal to walk
- Pain inside joints rather than muscles
- Migratory pattern—pain moving between joints
- Associated symptoms—fever, rash, fatigue, headaches
- Recent tick exposure or outdoor activities in endemic areas
Even one red flag warrants investigation.
How Lyme Arthritis Presents in Children
Lyme arthritis typically affects large joints, particularly the knee. Children develop visible swelling, warmth, and limitation of movement persisting for days to weeks. Pain may migrate from knee to ankle to wrist over weeks or months.
Children limp, avoid stairs, or refuse to participate in sports. Parents notice behavioral changes—a previously active child becomes sedentary because movement hurts.
Lyme arthritis often appears months after initial tick exposure, long after any rash or fever has resolved. Many children have no recalled tick bite. This delayed onset contributes to misdiagnosis as growing pains.
The Diagnostic Challenge
Growing pains is a clinical diagnosis requiring no testing. When pediatricians hear “leg pain at night,” they often provide reassurance without examination or evaluation. This fails when Lyme disease is the cause.
Children with true Lyme arthritis typically show positive serology because joint symptoms appear late when antibody response is established.
A child with persistent knee swelling following summer camp deserves Lyme testing even if parents describe “growing pains.”
Why This Distinction Matters
Growing pains require no treatment beyond reassurance. Children outgrow the condition without intervention.
Lyme arthritis requires antibiotics. Without treatment, inflammation may persist, and some children develop chronic arthritis damaging cartilage. Early treatment prevents these outcomes.
The growing pains label delays diagnosis. Months pass while parents wait for symptoms to resolve. By the time Lyme is recognized, children have experienced unnecessary pain and face more difficult recovery.
Frequently Asked Questions
How can I tell if my child has growing pains or Lyme disease?
True growing pains occur only at night in muscles (not joints), last 10-30 minutes, and never cause limping or swelling. Lyme arthritis causes persistent daytime joint pain, visible swelling, and often limping. If your child has joint swelling, daytime pain, or walks abnormally, investigation beyond growing pains is needed.
Can Lyme disease cause leg pain at night?
Yes, but Lyme arthritis also causes daytime symptoms. If pain occurs only at night with no daytime symptoms, swelling, or limping, growing pains is more likely. Lyme disease typically produces persistent or recurring joint pain throughout the day.
What does Lyme arthritis look like in children?
Lyme arthritis typically causes visible knee swelling with warmth and limited range of motion. Children may limp, avoid stairs, or refuse to participate in sports. The swelling persists for days to weeks and often appears months after tick exposure.
Do growing pains cause knee swelling?
No. True growing pains never cause visible swelling, warmth, or limitation of joint movement. Any joint swelling requires medical evaluation to rule out arthritis, including Lyme disease.
Can a child have both growing pains and Lyme disease?
While theoretically possible, any persistent, daytime, or joint-based pain should be evaluated for Lyme disease rather than attributed to growing pains. Don’t let the growing pains label prevent investigation of treatable infection.
Related Reading
- Pediatric Lyme Disease: Why Children Are Often Misdiagnosed
- Knee Swelling in a Child with Lyme Disease
- MRI Can Help Identify Lyme Arthritis in Children, Avoid Unnecessary Surgery
- Is My Child’s ADHD Actually Lyme Disease?
References
- Gerber MA, Shapiro ED, Burke GS, et al. Lyme disease in children in southeastern Connecticut. New England Journal of Medicine. 1996;335(17):1270-1274.
- Stiehm ER. Distinguishing between arthritis and growing pains in children. Pediatric Clinics of North America. 2005;52(3):687-702.
