Etanercept in the treatment of SAPHO syndrome: Which place?

Synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome (SAPHO) is a rare disease combining skin, bone, and joint manifestations. Its treatment remains a debated issue in the absence of a valid therapeutic strategy. The experience with tumor necrosis factor alpha (TNF alpha)-blocking agents is still small but encouraging. This therapy is reserved for refractory cases. The most commonly used agent is infliximab. Only few cases treated by etanercept have been reported in the literature. We report a new case treated by this biologic therapy and discuss its place in the treatment of SAPHO syndrome. A 30-year-old male, with a history of left clavicular osteitis that required surgical bone biopsy to rule out infection and malignancy, was admitted to the rheumatology department because of recurrent anterior chest pain, lower limb arthralgia, and sacroiliac pain. Laboratory findings revealed an inflammatory syndrome. Conventional radiography and computed tomography (CT) scan of the sternocostoclavicular region showed sclerosis and hyperostosis of the left clavicle. Right sacroiliitis was diagnosed based on the radiographic findings. Moreover, the patient reported palmoplantar pustulosis, thereby strengthening the diagnosis of SAPHO syndrome. As conventional treatment based on methotrexate, corticosteroids, and zoledronic acid was not effective, etanercept was initiated with good and rapid clinical and biological improvement. The diagnosis and treatment of SAPHO syndrome are challenging due to the heterogeneity of symptoms and unknown pathogenesis. Etanercept can be an effective therapy, especially in refractory cases. Further studies are needed in order to establish a therapeutic strategy.