Clinical and radiologic evolution of synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome: a single center study of a cohort of 71 subjects.

Objective: To assess the basic features and outcomes of synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome.

Methods: We identified all patients seen in our unit between 1990 and 2008 diagnosed according to the proposed inclusion criteria with SAPHO syndrome, who had a followup of at least 2 years.

Results: Seventy-one patients (48 women, 23 men) with SAPHO syndrome were identified. The median disease duration at the end of followup was 10 years (interquartile range [IQR] 7-15 years), and the median followup duration was 11 years (IQR 6-11.5 years). Six patients were diagnosed with Crohn's disease. Fourteen patients had never had cutaneous involvement, but 8 patients presented >1 skin manifestation. Nine patients (13%) presented a limited (<6 months) monophasic disease course, 25 cases (35%) had a relapsing-remitting course, and 37 patients (52%) had an acute painful phase with a prolonged course lasting >6 months. A total of 4% of the patients were HLA-B27 positive. Female sex (odds ratio [OR] 7.2, 95% confidence interval [95% CI] 2.2-22.9) and the presence at onset of anterior chest wall (ACW) involvement (OR 5.7, 95% CI 1.8-18.1), peripheral synovitis (P = 0.0036), skin involvement (OR 10.3, 95% CI 3.4-31.1), and high values of acute-phase reactants (OR 7.7, 95% CI 2.7-22) were correlated with a chronic disease course and involvement of new osteoarticular sites.

Conclusion: A chronic course is the more common evolution of SAPHO syndrome. Female sex, elevated erythrocyte sedimentation rate and C-reactive protein values, ACW involvement, peripheral synovitis, and skin involvement at the onset seem to be associated with a chronic course.