Disease characteristics among pediatric patients with coexisting localized scleroderma and inflammatory arthritis may vary widely, according to study results published in the European Journal of Rheumatology.

According to the researchers, a majority of patients with LS and inflammatory arthritis who received methotrexate (MTX) did not experience arthritis improvements in response to MTX and tumor necrosis factor inhibitor combination therapy, indicating that LS coexisting with inflammatory arthritis may be less likely to respond to traditional therapies for inflammatory arthritis or juvenile idiopathic arthritis (JIA).

In this study, investigators conducted a retrospective chart review of 8 pediatric patients with both LS and inflammatory arthritis to determine the association of inflammatory arthritis in pediatric patients with LS based on timing of disease onset, site of disease involvement, presence of autoantibodies, and treatment regimens. All patients were aged <19 years; patient data were identified from electronic medical records using diagnostic codes for morphea (ICD-9 701.0 and ICD-10 L94.0) and linear scleroderma (ICD-9 701.0 and ICD-10 L94.1).

Results indicated that among 87 patients with LS, 8 (9%) had coexisting inflammatory arthritis. Patients were followed up for a mean of 7 years. Of the 8 patients (median age of initial rheumatic disease diagnosis, 7.5 years; mean age, 8.9±4.2 years), 4 (50%) had LS lesions over arthritic joints. All 8 patients were diagnosed with a form of JIA in addition to LS. The JIA subtypes, according to the International League Against Rheumatism, varied widely in 1 (12.5%) patient with enthesitis-related JIA, 2 (25%) patients with psoriatic JIA, 2 (25%) patients with oligoarticular JIA, and 3 (37.5%) patients with RF-negative polyarticular JIA. Although arthritis distribution varied, all patients had ≥1 small joint affected, and 5 (62.5%) had ≥1 large joint affected. Timing of disease onset of LS and inflammatory arthritis also varied widely; 3 (37.5%) patients had LS lesions preceding the appearance of clinical arthritis, and 3 (37.5%) with arthritis preceding the appearance of LS. A total of 2 (25%) patients had a simultaneous diagnosis of LS and arthritis.

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While all patients received MTX, only 3 (37.5%) received systemic steroids during treatment. A wide variety of second-line medications and dosages were prescribed, with varying clinical effects. Three (37.5%) patients achieved full arthritis remission, 1 with MTX monotherapy and 2 using an additional second-line medication (1 patient with leflunomide monotherapy and 1 with mycophenolate mofetil + etanercept). Three (37.5%) patients showed arthritis improvements with second-line medications (1 with MTX + etanercept, 1 with mycophenolate mofetil + infliximab, and 1 with MTX + adalimumab). Regardless of the medication prescribed, all patients had improvement or stabilization in LS lesions.

Study investigators concluded that despite the limitations of such a small sample size, “All patients showed an improvement in the morphea lesions with the use of MTX, but the arthritis had variable responses. Although the comorbid presentation of LS and inflammatory arthritis suggests an underlying systemic inflammatory component and perhaps even a shared immunopathology and a genetic component, additional studies are needed to clearly understand the relationship between localized scleroderma and inflammatory arthritis, and subsequently design the most appropriate treatment plan.”

Reference

Reiff D, Crayne CB, Mannion ML, Cron RQ. Characteristics of coexisting localized scleroderma and inflammatory arthritis [published online December 3, 2019]. Eur J Rheumatol. doi:10.5152/eurjrheum.2019.19147