Pediatric eosinophilic fasciitis: similarities and differences with adult forms.

The purpose of this study was to identify pediatric eosinophilic fasciitis, which is an extremely rare condition, in order to describe their clinical, paraclinical, and therapeutic characteristics. We made a call for observations via societies for pediatric rheumatology in France and surrounding countries and collected clinical and paraclinical data of the cases fulfilling the diagnostic criteria. Eight patients under 18 years of age with confirmed eosinophilic fasciitis followed between April 2004 and July 2022 in France, Germany, Italy, and Spain were included. The median age of onset of symptoms was 8.7 years (range 3 to 12.6). All patients had skin and joint involvement at diagnosis. Eosinophilia was present at diagnosis in 5/8 patients and 5/7 patients presented hypergammaglobulinemia. All the patients had an MRI, and in 6, we observed thickened fascia with a T2 hypersignal. Five patients had undergone a full-thickness biopsy showing a polymorphic lymphoplasmacytic infiltrate of the fascia in all and the presence of eosinophils in 4 of them. All the patients were treated with corticosteroids with variable regimens and all received at least an immunosuppressant. Conclusion: To our knowledge, this is the largest pediatric series of eosinophilic fasciitis. The clinical and paraclinical presentation seems similar to that of adults except for a form that appears to be distinguished with isolated joint contractures, and hypergammaglobulinemia which appears to be more frequent in children. Dermatological and pathological expertise and MRI are key elements of the diagnosis. The most consensual treatment includes physiotherapy, prolonged corticosteroid therapy, and methotrexate as first-line therapy. What is Known • Eosinophilic fasciitis is a rare condition, especially in children with approximately 60 reported pediatric cases. • Some pediatric specificities tend to emerge from some reports. What is New • Possible isolated joints contractures and more frequent hypergammaglobulinemia seem to characterize pediatric eosinophilic fasciitis in comparison with adult forms. • The most frequently used first-line therapy combines physiotherapy, corticosteroids and methrotrexate.