Lyme Arthritis in Children
Lyme arthritis in children is one of the most common late manifestations of Lyme disease. It typically develops weeks to months after infection with Borrelia burgdorferi, the bacterium transmitted by tick bites.
Lyme arthritis is also one of the most common musculoskeletal complications of pediatric Lyme disease. Unlike early Lyme disease, which may include rash or flu-like symptoms, joint swelling may appear later and may be the first sign of infection recognized by families or clinicians.
For a discussion focused specifically on early recognition of joint swelling and limping, see Lyme arthritis symptoms in children.
How Lyme Arthritis Develops
Lyme arthritis develops when the immune system responds to infection with Borrelia burgdorferi. By the time joint swelling appears, earlier symptoms such as fever, fatigue, or rash may already have resolved.
Because of this delay, families often do not connect joint symptoms with a prior tick exposure.
Which Joints Are Affected
Large joints are most commonly affected in Lyme arthritis. The knee is involved in the majority of pediatric cases.
Other joints that may be affected include:
- ankle
- elbow
- wrist
- hip
In some children, inflammation may involve smaller joints of the hands or feet, although this is less common.
Joint swelling may occur in a single joint or shift from one joint to another over time.
Diagnosing Lyme Arthritis in Children
Diagnosis combines clinical evaluation with laboratory testing. Clinicians consider several factors:
- history of outdoor exposure in tick-endemic areas
- swelling of one or more joints
- Lyme serologic testing
- exclusion of other causes of arthritis
Because septic arthritis can also present with a swollen joint, careful evaluation is important when children present with acute joint inflammation.
In selected cases, imaging or joint fluid analysis may help distinguish Lyme arthritis from other joint disorders.
Conditions That May Mimic Lyme Arthritis
Several childhood conditions can resemble Lyme arthritis and should be considered during evaluation. These include:
- juvenile idiopathic arthritis (JIA)
- systemic juvenile arthritis (Still’s disease)
- septic arthritis
- reactive arthritis
- joint injury or trauma
Because of these possibilities, evaluation by pediatric specialists such as orthopedic surgeons or rheumatologists may be important when children present with unexplained joint swelling.
In regions where Lyme disease is common, some children initially suspected of having juvenile arthritis are ultimately diagnosed with Lyme arthritis after appropriate testing.
Treatment of Lyme Arthritis
Most children with Lyme arthritis improve with antibiotic therapy.
Common oral antibiotics used in children include:
- doxycycline
- amoxicillin
- cefuroxime
Treatment typically lasts several weeks, and swelling usually improves gradually after therapy begins.
Antibiotic-Refractory Lyme Arthritis
A small proportion of children develop persistent joint inflammation despite initial antibiotic therapy, sometimes referred to as antibiotic-refractory Lyme arthritis.
In clinical practice, some children with persistent symptoms improve after additional treatment courses or when coinfections are identified and addressed.
Management of persistent inflammation may also involve anti-inflammatory medications or referral to a pediatric rheumatologist.
Long-Term Outlook
The prognosis for children with Lyme arthritis is generally favorable. Most children recover fully with treatment.
Joint swelling may take time to resolve, and some children experience intermittent symptoms during recovery. Long-term joint damage is uncommon.
Clinical Perspective
In clinical practice, Lyme arthritis often presents as sudden swelling of a knee in an otherwise healthy child. Because the swelling may appear weeks after infection, the connection to Lyme disease may not be immediately recognized.
When unexplained joint swelling occurs—particularly in children living in tick-endemic areas—Lyme disease should remain part of the differential diagnosis.
References
- Glaude PD, Huber AM, Mailman T, Ramsey S, Lang B, Stringer E. (2015). Clinical characteristics, treatment and outcome of children with Lyme arthritis in Nova Scotia. Canadian Journal of Infectious Diseases and Medical Microbiology, 26(6), 321–324. https://doi.org/10.1155/2015/152095
- Yen, Y.-M., Sanborn, R. M., Donohue, K., Miller, P. E., Milewski, M. D., & Ecklund, K. (2022). Lyme arthritis in the pediatric knee: Clinical and magnetic resonance imaging differentiators. JBJS Open Access, 7(4), e22.00067. https://doi.org/10.2106/JBJS.OA.22.00067
