Chronic Nonbacterial Osteomyelitis in a Child with Previous Juvenile Dermatomyositis

Abstract

To the Editor: Chronic nonbacterial osteomyelitis (CNO) is a sterile osteitis of unknown etiology. The diagnosis is based on characteristic clinical, laboratory, and imaging features1. Currently, CNO is considered an autoinflammatory disorder. However, the association of CNO with inflammatory bowel diseases2, psoriasis3, and vasculitis suggests that both innate and adaptive immunity may contribute to pathogenesis. A 3-year-old girl presented with proximal muscle weakness, Gottron papules, and periorbital heliotrope rash. Erythrocyte sedimentation rate (ESR) was 30 mm/h (normal 0–12 mm/h); creatine kinase, aspartate aminotransferase, and lactate dehydrogenase were normal. Antinuclear autoantibody (ANA) titers were 1:320; antibodies against Jo-1, ribonuclear proteins, Smith, Ro, La, Scl-70, and double-stranded DNA were not detected. Muscle biopsy result was consistent with dermatomyositis. She was started on oral corticosteroids 1.5 mg/kg/day and methotrexate 0.5 mg/kg weekly. After 9 months, muscle strength normalized and treatment was discontinued. Family history revealed that her brother and maternal grandmother had psoriasis and a paternal uncle was diagnosed with Crohn disease (Figure 1). Figure 1. The family history of a child with chronic recurrent nonbacterial osteomyelitis and previous … Address correspondence to Dr. R.M. Laxer, Division of Rheumatology, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada. E-mail: ronald.laxer{at}sickkids.ca