Eosinophilic fasciitis in a child mimicking a myopathy

A 14-year-old boy was suspected of having a myopathy with joint contractures. He presented with progressive painless joint contractures of his right wrist and fingers, and reduced muscle strength of his right arm, without obvious skin changes. Laboratory investigation showed a normal CK, hypergammaglobulinemia and eosinophilia. Ultrasonography revealed thickened fasciae in the forearm. A full thickness biopsy confirmed the diagnosis of eosinophilic fasciitis. The contractures diminished quickly with prednisolone and methotrexate. The ultrasound scans 2 years after diagnosis showed improvement, although some thickening of the fasciae was still present, indicating residual changes. In conclusion, eosinophilic fasciitis has to be regarded as a differential diagnosis of painless joint contractures in children. Ultrasonography can be helpful to suspect the diagnosis.