Chronic recurrent multifocal osteomyelitis (CRMO) and synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome with associated neutrophilic dermatoses: a report of seven cases and review of the literature.

A growing body of literature has identified the association between neutrophilic dermatoses and multifocal, aseptic bone lesions in children, termed chronic recurrent multifocal osteomyelitis (CRMO). Classically, patients present with swelling, pain, and impaired mobility of the affected area, with skin lesions developing concurrently or in the future. Bone biopsy reveals inflammatory changes consistent with infectious osteomyelitis, but cultures and histologic staining invariably fail to identify an infectious source. Patients are refractory to antibiotic therapy, but dramatically respond to systemic steroids and may need to be maintained on low-dose steroids to prevent relapse. Numerous authors have suggested that CRMO and synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome lie along the same clinical spectrum. In fact some believe that CRMO is the pediatric presentation of SAPHO. The two syndromes share numerous characteristics, including osteitis, a unifocal or multifocal presentation, hyperostosis, and pustulosis, which all occur in a generally healthy individual. Our seven patients, five of whom were diagnosed with CRMO, and two of whom were diagnosed with SAPHO syndrome further strengthen the idea that CRMO and SAPHO syndrome do indeed lie along the same clinical spectrum. In addition, we include two rare cases of pediatric Sweet's syndrome with evidence of pathergy.