[Arthropathies related to HLA-B27].

Spondyloarthropathies represent an important problem within the field of chronic childhood arthropathies. Nosology and differential diagnosis are yet unclear. It is important to distinguish spondyloarthropathies from JCA because biological aspects of affected patients, clinical findings, extraarticular manifestations and prognosis are very different. Ankylosing spondyloarthritis is the prototype of spondyloarthropathies: at the beginning, axial involvement is rare; it may develop during the following years or it may not occur. Enthesopathy is an important finding of spondyloarthropathies. Diseases with joint involvement, HLA B27 related, as ankylosing spondyloarthritis, psoriatic arthritis. Reiter's syndrome or arthritis associated with chronic bowel disease, enter the chapter of spondyloarthropathies. Children with familial history of spondyloarthropathies showing enthesopathy, "sausage fingers" and with the presence of HLA B27, may be classified in the group of spondyloarthropathies. Children with a chronic arthritis with pauciarticular onset, B27 positive, without any sign and finding spondyloarthropathies, should be classified as JCA from the beginning. A follow up of children affected with chronic arthritis is fundamental for a more correct classification of the disease.