About SJIA About SJIA

What is SJIA?

Many people think that arthritis affects only adults. But the truth is that people of all ages, including children, can experience many different types of arthritis. When arthritis does occur in children, it's commonly referred to as juvenile arthritis.

But what is Systemic Juvenile Idiopathic Arthritis (SJIA)? And how is it different from other types of juvenile arthritis? To get an idea, let's break down the meaning of SJIA:


Systemic means inflammation that affects the entire body.


Juvenile means that it occurs in a young person, or a group of young people.


Idiopathic means the exact cause of the disease is unknown.


Arthritis means that there's inflammation of one or more joints, which can cause pain, swelling, stiffness, and loss of motion.

SJIA (also known as Still's Disease) is a rare and chronic autoinflammatory disease that affects the body's immune system, causing it to attack healthy cells in the body. This can lead to SJIA symptoms including fevers, rash, and painful and/or swollen joints. Children usually develop SJIA at or around 2 years of age. Although the cause of SJIA is unknown, it occurs equally among boys and girls.

About 300,000 kids in the United States have some form of arthritis. SJIA accounts for about 10% of all cases* of juvenile idiopathic arthritis.

*Estimate based on data obtained between 2001 and 2004.

If your child is diagnosed with SJIA, ask your child's doctor about ILARIS®, the once-monthly injectable biologic medicine that's FDA approved for active SJIA in children 2 years of age and older. Find out more about ILARIS and whether ILARIS is right for your child.

Next: Signs and Symptoms