Biologics for rare inflammatory diseases: TNF blockade in the SA PHO syndrome.

INTRODUCTION SAPHO is an invalidating syndrome characterised by Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis. The low prevalence and heterogeneous presentation often leads to a significant diagnostic delay. Here, we provide an up-to-date overview of current insights into the pathogenesis and different treatment options. In addition, we describe the effects of anti-TNF treatment in three refractory cases. CASE REPORTS Patient A is a 25-year-old female with hidradenitis suppurativa, inflammatory back pain and painful joints. After diagnosis, anti-TNF treatment was started resulting in clinical improvement. Patient B is a 44-year-old woman who presented with acne, palmoplantar pustulosis and anterior chest wall pain. Bone scintigraphy showed increased uptake at the anterior chest wall. Treatment with bisphosphonates resulted in temporary improvement and subsequent treatment with anti-TNF induced long-term clinical improvement. Patient C is a 37-year-old woman with palmoplantar psoriasis, relapsing hidradenitis and inflammatory back pain. MRI revealed osteitis of the pubic bone. Anti-TNF was started for SAPHO syndrome. However, despite a clinical response, our patient discontinued treatment, resulting in rapid deterioration. Anti-TNF treatment was re-introduced followed by clinical improvement. CONCLUSION These case reports illustrate, consistent with the current literature, that TNF blockers can be considered for treatment of refractory SAPHO syndrome.