Is it Lyme arthritis or JIA?


A Lyme arthritis diagnosis requires a two-step testing approach. False positives are complex and common.

The authors of a review article on the differentiating factors of Lyme arthritis in children recommend that patients suspected of having juvenile idiopathic arthritis (JIA) in endemic regions for Lyme disease, may have Lyme arthritis and should be screened for Lyme disease.

“Two-tier testing is advisable when a patient’s history suggests a possibility of potential tick bite,” writes Elżbieta Smolewska this month in the journal Pediatric Rheumatology. “The development of consistent worldwide guidelines would simplify the diagnostic process in everyday pediatric practice.”

In the absence of such guidelines, Dr. Smolewska and colleagues reviewed the scientific evidence for Lyme arthritis in children.

Clinical features

In the United States, Borrelia burgdorferi sensu stricto is the main cause of Lyme arthritis, while in Europe, two other genospecies of Borrelia burgdorferi have been implicated in Lyme disease:  B. garinii and B. afzelii. The two are different in that an infection of the latter occurs within a short period of time from a tick bite, as opposed to a Borrelia burgdorferi sensu stricto infection which can manifest months later any month of the year, not only during summer months.

Erythema migrans, a rash associated with infection, is sometimes accompanied or preceded by fatigue, fever, headache, stiff neck, myalgias, arthralgias, nausea and dysesthesia. But few patients - only 18 percent according to Glaude et al. - report having had a rash. The majority of patients, 72 percent, reported arthritis as their first symptom and 76 percent did not know they were bitten by a tick.

In children, Lyme arthritis can affect the large synovial joints causing pain. The joint can swell repeatedly and asymmetrically with moderate inflammation, sometimes causing no pain. In 90 percent of cases, the knee is affected, followed by the ankle. Arthritic pain can resemble mono or oligoarticular JIA. Thompson et al. reported that 38 percent of patients could not put weight on affected limbs.  


ELISA (enzyme-linked immunosorbent assay) is the standard test used to confirm a Lyme arthritis diagnosis. If it is positive, it should be followed by a western immunoblot test (WB). The Centers for Disease Control and Prevention defines a positive WB test as one that has two of three specified bands on the IgM WB or five of 10 specified bands on the IgG WB. But the authors of the review caution that WB is insensitive in early phases of Lyme disease “due to slow development of the humoral immune response.” And, because it is test that depends on visual scoring, it has a high risk for false results, which is why it needs to be performed at a reference laboratory.  [[{"type":"media","view_mode":"media_crop","fid":"59798","attributes":{"alt":"(©Narikan/","class":"media-image media-image-right","id":"media_crop_7011814757099","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"7534","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; float: right;","title":"(©Narikan/","typeof":"foaf:Image"}}]]

The C6 antibody test is a newer, first-step ELISA test that offers a comparable to higher sensitivity than the standard two-step test. C6 uses a peptide from the constant region of a B. burgdorferi protein called Vmp-like sequence lipoprotein E (VlsE).

In the absence of diagnostic testing, if a patient exhibits signs and symptoms of less than 30 days, it could be considered positive based on IgM or IgG. But, if a patient has been showing signs and symptoms for more than 30 days, which is true in most Lyme arthritis cases, IgG positivity is required to confirm the diagnosis. False positive test results can occur due to cross-reactivity, especially in patients with infectious mononucleosis or when rheumatoid factor (RF) is present.


The Infectious Diseases Society of America (IDSA) recommends treating Lyme arthritis affected children with a 28-day course of oral antibiotics with either doxycycline (4 mg/kg per day in two divided doses, maximum of 100 mg per dose) or cefuroxime (axetil 30 mg/kg per day in two divided doses, maximum of 500 mg per dose) or amoxicillin (50 mg/kg per day in three divided doses, maximum of 500 mg per dose).

Doxycycline is preferred because it is effective against B. burgdorferi sensu lato, however, it is not recommended in children younger than 8 years old due to the risk of discoloring teeth.

After initial treatment, if the infection persists, a four-week course of oral antibiotics or a two to four-week course of intravenous ceftriaxone should be administered, but there is no benefit in prolonged antibiotic treatment beyond the second course. Berende et al. showed there was no significant difference of health-related quality of life between groups of patients who received two weeks of intravenous ceftriaxone and then continued treatment with a 12-week course of oral doxycycline, clarithromycin plus hydroxychloroquine or placebo.

In persistent cases of antibiotic-refractory Lyme arthritis, symptoms of joint pain and swelling can be treated with non-steroidal anti-inflammatory drugs (NSAIDs), disease-modifying antirheumatic drugs (DMARDs), or intra-articular corticosteroids.


Lyme arthritis eventually resolves spontaneously, the researchers wrote, but it can take years in extreme cases. Tory et al. reported that 23 percent of pediatric patients had persistent synovitis after eight weeks of oral antibiotic therapy or four weeks of intravenous therapy or both.

More from Rheumatology Network



Krzysztof Orczyk, Joanna Świdrowska-Jaros and Elżbieta Smolewska. "When a patient suspected with juvenile idiopathic arthritis turns out to be diagnosed with an infectious disease – a review of Lyme arthritis in children," Pediatric Rheumatology. Orczyk et al. Pediatric Rheumatology (2017) 15:35. DOI 10.1186/s12969-017-0166-0

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