Blau syndrome (juvenile systemic granulomatosis)
Blau syndrome is an inflammatory disorder that primarily affects the skin, joints, and eyes. Signs and symptoms begin in childhood, usually before age 4. Arthritis is a common feature of Blau syndrome. In affected individuals, arthritis is characterized by inflammation of the synovium. Synovitis usually begins in the joints of the hands, feet, wrists, and ankles. As the condition worsens, it can restrict movement by decreasing the range of motion in many joints.