Background/Purpose: The SAPHO syndrome is a rare inflammatory disorder of bones, joints and skin first coined by Chamot in 1987 characterized by synovitis, acne, pustulosis, hyperostosis and osteitis¹. No validated diagnostic criteria exist; diagnostic delay is not uncommon and observational data from the Western Hemisphere is sparse

Methods: Adult patients with a diagnosis of SAPHO seen between 2001 and 2018 at a single tertiary referral center were retrospectively identified. Cases were reviewed by a physician abstractor to determine whether they fulfilled either of the following 2 proposed criteria for SAPHO: Benhamou^1,2 or modified Kahn (2003)³. Sociodemographics, clinical characteristics, laboratory parameters, radiology, histopathology, management and outcomes were abstracted from direct medical record review. Patients with non-inflammatory bony lesions, infectious osteitis and CRMO were excluded.

Results: Twenty-one patients with complete clinical and treatment data were identified (71% female, 76% Caucasian). The average age at the time of diagnosis was 36.9 ± 13.4 years and the mean time from symptom onset to diagnosis was 3.4 years. 20/21 had cutaneous involvement: 10 with palmoplantar pustulosis or psoriasis vulgaris and 10 with severe acne. Osteoarticular manifestations included anterior chest wall/clavicle 15 (71%), peripheral arthritis 9 (43%), inflammatory back pain 8 (38%) and 2 (10%) with mandibular osteitis. Uveitis and mucositis were uncommon (2 out of 21 cases). 52% had elevated inflammatory markers at diagnosis while HLA-B27 positivity was uncommon (1/11). 13 of 13 radionuclide bone scans performed were positive while 8 of 9 MRI’s were diagnostic.

18 patients (86%) were treated with NSAIDs; addition of immunosuppressive therapy with oral DMARDs (n=14, 66%) and TNF inhibitor (n=12, 57%) was quite common. 9 of 12 patients treated with TNFi experienced loss of efficacy requiring an alternate TNF inhibitor or switch to IL 17 or 23 blockade. 6/21 received oral antibiotics (doxycycline or penicillin); 50% of whom responded well. 7/21 proved refractory requiring bisphosphonate therapy; 5/7 responded at time of last follow up. Outcomes were favorable overall with 15 (71%) being in/near remission at the end of the follow up period (mean of 3 years). 2 patients required reconstructive surgery; and they both had active disease at last visit.

Conclusion: This large case series presents a heterogenous group of SAPHO patients with a long period of follow up. A significant delay was noted between symptom onset and diagnosis. Concomitant cutaneous and osteoarticular manifestations were seen in the majority (20) of patients. HLA B27 was frequently negative in our group; advanced imaging with bone scan or MRI helped to confirm the diagnosis. Though NSAID and DMARD use were quite common, biologic and/or bisphosphonate therapy was frequently required. Female predominance and chest wall involvement in this series may explain the lack of response to NSAIDs⁴.Further studies are needed to guide diagnostic strategies and management. Greater awareness and multi-disciplinary collaboration are imperative in the provision of care to these patients.

References

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/clinical-manifestations-and-management-of-us-patients-with-sapho-synovitis-acne-pustulosis-hyperostosis-osteitis-syndrome-a-retrospective-study/