(BMJ)—A 13-yo boy presented w/ fever, truncal rash, and arthralgias in the pelvis and knees. Exam: severe papulopustular acne on chest and back. Labs: elevated CRP, WBC 16.8x109/L. Abdominal U/S negative. Fecal calprotectin negative. MRI positive for sacroiliitis. What is the dx?
Sweet syndrome
Psoriatic arthritis
SAPHO syndrome
Majeed syndrome
Deficiency of IL-1 receptor antagonist (DIRA)
You are correct. SAPHO syndrome is a rare condition characterized by skin and osteoarticular manifestations. Skin manifestations include severe acne and/or palmoplantar pustulosis, which may precede the osteoarticular sx. The axial skeleton is almost always affected, w/ involvement of sternocostal and sternoclavicular joints, and/or sacroiliitis. MRI can detect early osteoarticular signs of the dz. Corticosteroids and abx are generally 1st-line tx, but in most cases immunosuppressive tx (MTX or infliximab) is required. Pediatricians should be aware of SAPHO syndrome in children w/ severe acne and osteoarticular manifestations. This pt improved w/ oral MTX and isotretinoin.

Arch Dis Child Published Online First: 02 February 2019. doi: 10.1136/archdischild-2018-316620