Successful treatment of SAPHO syndrome with apremilast

SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome is a rare disease with inflammatory osteoarticular and skin involvement. The pathogenesis of SAPHO syndrome remains unclear, but evidence suggests it may be an autoinflammatory disease triggered upon exposure to infectious agents in genetically predisposed individuals. Induction of the interleukin (IL)‐23/T helper 17 axis in addition to neutrophil activation seem to play a key role, and therapies targeting these immunological pathways, including tumour necrosis factor (TNF) inhibitors, ustekinumab, secukinumab and the IL‐1 inhibitor anakinra, are potential treatment options that need further investigation. Here we report a case of a 24‐year‐old woman with SAPHO syndrome who presented at our clinic with palmoplantar pustulosis and sternoclavicular joint involvement. Previous treatments with topical steroids and keratolytics combined with nonsteroidal anti‐inflammatory drugs, intravenous methylprednisolone, methotrexate and sulfasalazine had all failed to improve symptoms. Therapy with etanercept was not tolerated, and because of a previous demyelinating peripheral neuropathy, further treatment with TNF inhibitors was avoided. We initiated ustekinumab 45 mg, which improved skin manifestations but not joint pain. Dose escalation to 90 mg initially improved joint pain, but the dose had to be reduced to 45 mg again because of increased infections. During subsequent 45‐mg ustekinumab treatment, joint pain exacerbated so we switched to adalimumab which caused an exacerbation of the disease, so we switched to secukinumab, which improved skin and joint symptoms significantly but was associated with a pustular hypersensitivity reaction. Finally, we began treatment with apremilast, a pan‐cytokine approach, resulting in stabilization of the skin and joint symptoms without side‐effects. To our knowledge, this is the first case report of apremilast as a treatment for SAPHO syndrome.