SAPHO Syndrome Summary



What?

SAPHO syndrome is a rare chronic inflammatory disorder of bone, joint, and skin characterized by:

• Synovitis (inflammation of the joints)

• Acne (Acne conglobata or fulminans)

• Pustulosis (thick yellow blisters containing pus) often on the palms and soles

• Hyperostosis (increase in bone substance)

• Osteitis (inflammation of the bones)



Why?

• Etiology unknown: Autoinflammatory disorder



When to suspect?

• Pustular skin lesions + Rheumatic pain



Clinical Features:

• Synovitis: most often a nonerosive inflammatory arthritis

• Acne/Pustulosis: Variety of acneiform and neutrophilic dermatoses

• Skin findings: Hidradenitis suppurativa, palmar pustular pustulosis, pustular psoriasis, psoriasis vulgaris, Acne conglobata or fulminans

• Hyperostosis: Sclerotic bone changes with trabecular and cortical thickening

• Osteitis: pain, tenderness +/- sometimes swelling of the bone

• Bone and joint involvement: May involve anterior chest wall, parts of the axial skeleton-sacroiliac joint and spine, & medium to large lower-extremity joints



Diagnosis:

• A clinical diagnosis

• Rule out other causes such as infectious, malignant, or other etiology

• Laboratory findings: Nonspecific inflammatory changes: CRP, ESR

• Imaging: 

    - Plain radiographs of affected areas and if negative then whole-body scintigraphy.

    - MRI: inflammation of the bone marrow or joints at characteristic sites such as the collar bone, breast bone, pelvis, heel, and lower jaw



Treatment:

• Osteoarticular manifestations: NSAIDs/glucocorticoid

• SAPHO syndrome with palmoplantar pustulosis: oral retinoid

• SAPHO syndrome with acne: antibiotics with antiinflammatory properties e.g Tetracyclines etc

TNF blockers had the best response rate in osteoarticular and skin disease. Other biologics reported to be efficacious include IL-1 inhibitors, IL-17 inhibitors, and IL-23 inhibitors.



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