SAPHO Syndrome

In 1987, Chamot et al attempted to unify the various descriptions of osteoarticular disease associated with skin manifestations into a syndrome with the acronym SAPHO: synovitis, acne, pustulosis, hyperostosis, and osteitis (Chamot et al., 1987). Furthermore, the clinical feature of aseptic chronic recurrent multiple osteomyelitis (CRMO) accompanied by pustulosis with its typical presentation in the pediatric population justifies the inclusion of CRMO into the same nosologic group as the SAPHO syndrome according to several authors (Juri et al., 1988, Kahn et al., 1994). The differentiating clinical features of pediatric CRMO and adult hyperostosis with osteitis in patients with SAPHO syndrome seem to be mainly in localization of inflammation: in pediatric CRMO more often the extremities, in adults the axial skeleton preferentially with costosternoclavicular region (Rohekar et al., 2006). The wide spectrum of SAPHO syndrome describes overlapping clinical radiologic and pathologic characteristics that SAPHO shares with well-defined rheumatologic and dermatologic disorders, such as psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Against this background the SAPHO syndrome has been often controversially discussed and more than 50 competing terms have been proposed for these or for very similiar entities, among others pustulotic arthro-osteitis and acquired hyperostosis syndrome (AHS) (Kirchhoff et al., 2003). With the increase in reports dealing with growing numbers of patients with SAPHO syndrome, this disease entity should be suspected in patients who fulfil one of the following diagnostic criteria (Assmann et al., 2011): (1) Osteoarticular manifestations with dermatosis like acne conglobata, acne fulminans, or palmoplantar pustulosis (PPP); (2) axial or appendicular osteitis and hyperostosis with or without dermatosis; (3) CRMO involving the axial or appendicular skeleton with or without dermatosis. However, in this broad spectrum of osteoarticular and chronic dermatological manifestations, osteitis seems to be the leading characteristic finding to determine the entity of SAPHO syndrome.