Active Polyarticular Juvenile Idiopathic Arthritis (pJIA)

What is Active Polyarticular Juvenile Idiopathic Arthritis (pJIA)?

Active Polyarticular Juvenile Idiopathic Arthritis (pJIA) is a type of inflammatory arthritis that occurs in children under the age of 16. It is a form of a childhood arthritis. It involves at least five different joints that become swollen, inflamed, and tender, usually for an extended period of time. pJIA is also sometimes called polyarthritis​ or polyarticular arthritis.


The symptoms of pJIA vary depending on the individual, but the primary symptom is pain and swelling of five or more joints. Other signs of the condition may include:

  • Fever
  • Stiffness, particularly in the morning
  • Fatigue
  • Weight loss

In some cases, it can lead to damage of bones and other structures near the affected joints if left untreated.


Juvenile idiopathic arthritis is an autoimmune disorder, meaning that the immune system mistakenly attacks healthy tissues in the body as if they were a foreign invader. The cause of this condition is unknown, but certain factors have been linked to its development, such as genetics. Infections and injuries may also trigger the onset of the disease.


The diagnosis of pJIA begins with a physical examination. Your doctor may also ask you to provide details about your child's medical history. A variety of tests may be conducted to rule out other causes of joint pain and inflammation, such as blood tests, joint fluid analysis, X-rays, ultrasounds, or joint aspiration. Your doctor may also refer your child to a rheumatologist for further evaluation and diagnosis.


The main goal of treatment for pJIA is to reduce inflammation, and to control pain and other symptoms. Treatment plans may include medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), immunosuppressants, and biologic agents. Additionally, physical therapy, occupational therapy, and lifestyle changes such as diet and exercise may be advised to reduce inflammation and improve quality of life.