12 Types of Arthritis and How They Differ

7. Juvenile Idiopathic Arthritis - When Childhood Meets Chronic Disease

Juvenile idiopathic arthritis (JIA) encompasses a group of chronic arthritis conditions that begin before age 16 and persist for at least six weeks, affecting approximately 300,000 children in the United States. This complex group of disorders is classified into several subtypes based on the number of joints affected, presence of systemic symptoms, and specific clinical features. Oligoarticular JIA affects four or fewer joints in the first six months and is the most common subtype, particularly in young girls, often affecting large joints like knees and ankles. Polyarticular JIA involves five or more joints and can be either rheumatoid factor positive or negative, with the positive form more closely resembling adult rheumatoid arthritis. Systemic JIA presents with high spiking fevers, salmon-colored rash, lymphadenopathy, and hepatosplenomegaly in addition to arthritis, representing the most severe form. Enthesitis-related arthritis primarily affects boys and involves inflammation at tendon and ligament attachment sites, often progressing to involve the spine. Psoriatic JIA combines features of arthritis with psoriasis or a family history of the skin condition. Early diagnosis and treatment are crucial to prevent growth disturbances, joint contractures, and vision-threatening complications such as chronic anterior uveitis. Treatment approaches must consider the child's growth and development, often involving a multidisciplinary team including pediatric rheumatologists, ophthalmologists, physical therapists, and psychologists.