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, 950% 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.