Enthesitis-related arthritis: time to re-define?

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in childhood. Enthesitis-related arthritis (ERA) is one of the seven JIA subtypes classified by the International League of Associations for Rheumatology (ILAR). Due to inclusion and exclusion criteria, a pitfall of the ERA category is that it does not include all subsets of juvenile spondyloarthropathy, with many children ending up in the undifferentiated category. The ERA nomenclature also does not have a method for distinguishing between axial and peripheral disease, two phenotypes which vary in presentation and treatment requirements. This distinction is very important given the overall poor prognosis seen in ERA patients, specifically in those with axial involvement. Since axial involvement is more common and presents earlier than previously thought in ERA, the pediatric rheumatology community should develop more accurate and sensitive classification criteria based on disease course to assist in improving timely diagnosis and appropriate management.