Spondyloarthritides

1. Big picture

Spondyloarthritides (SpA) are a family of inflammatory rheumatic diseases that mainly affect the axial skeleton, sacroiliac joints, entheses, and peripheral lower-limb joints.

The classic exam pattern is:

Young patient + inflammatory back pain + morning stiffness + sacroiliitis ± enthesitis ± uveitis ± psoriasis ± inflammatory bowel disease ± preceding infection.

SpA is traditionally called seronegative spondyloarthritis because rheumatoid factor (RF) is usually negative. It is strongly associated with HLA-B27, especially ankylosing spondylitis and axial SpA.