Efficacy of Adalimumab on Severe Sapho Syndrome Likely Triggered by Isotretinoin

Background SAPHO (synovitis, acne, pustolosis, hyperostosis and osteitis) syndrome is a rare autoinflammatory chronic disorder, presenting with non-infectious inflammatory osteitis, sterile joint inflammation and skin manifestations including palmoplantar pustolosis and severe acne. It could be often misdiagnosed for its heterogeneous clinical presentation. Isotretinoin, which is commonly used for severe acne treatment, has been rarely described as possible trigger of osteo-articular manifestations, in particular sacroiliitis. Various biological treatment have been proposed in refractory patients.Case presentation The case of an adolescent male, affected by acne fulminans and depression, who presented with sacroiliitis after a 10-week treatment with isotretinoin is presented and discussed. After SAPHO diagnosis, the boy started NSAIDs therapy but the onset of bilateral gluteal hidradenitis suppurativa required the switch to a tumour necrosis factor (TNF)-α antagonist (adalimumab). Despite specific therapy with sertraline, the patient continued to complain severe depression, this symptom has been widely reported in patient with SAPHO.Conclusions Our case strengthens the hypothesis that isotretinoin could be a trigger of musculoskeletal involvement in SAPHO. The occurrence of hidradenitis suppurativa as additional clinical feature of SAPHO, already described in literature, supported the TNF-α blocker’s commencement in our patient. Furthermore, the good outcome of our case confirms the efficacy of ADA treatment in obtaining persistent clinical remission of cutaneous and osteoarticular symptoms in SAPHO syndrome.