SAPHO syndrome is characterised by any combination of:
S—Synovitis (90% of patients): oligo asymmetric (large > small joints), axial (sternal), and sacroiliac joints (unilateral).
A—Acne (18%): cystic acne conglobata, acne fulminans.
P—Pustulosis (66%): pustular psoriasis, palmoplantar pustulosis, or hidradenitis suppurativa.
H—Hyperostosis: especially of anterior chest well with sternocostoclavicular hyperostosis.
O—Osteitis: symphysis pubis, sacroiliitis (33%), spondylodiscitis, anterior chest wall, vertebral sclerosis more than long
The name was proposed in 1987 by Chamot et al because they were impressed by the association of a sterile arthritis (frequently involving the anterior chest) and various skin conditions. Etiology is unclear, although Propionibacterium acnes as a causative agent has been implicated. HLA-B27 is positive in 13% of cases. Therapy includes NSAIDs, intraarticular and systemic corticosteroids, sulfasalazine, doxycycline, intravenous bisphosphonates, methotrexate, and anti-TNF agents. Note that anti-TNF agents (especially infliximab) can exacerbate pustular psoriasis.