Which Kind of Arthritis Do You Have? 

Juvenile idiopathic arthritis (JIA) is an umbrella term for a whole bunch of different kinds of arthritis, including these: 

Oligoarthritis 

• The most common form of JIA 
• Typically affects one to four joints during the first six months of the disease and more joints later on 
• Often starts on just one side of the body, usually in a large joint, like the knee or ankle 
• Sometimes causes eye inflammation, called uveitis    
• Is more common among young females  than young males 

Polyarthritis    

• Affects five or more joints during the first six months of the disease, often in the same joints on both sides of the body, such as both wrists or both knees   
• Can cause problems in large joints that bear body weight, like hips and knees, as well as small joints, like those in the hands and feet 
• Can affect the neck and jaw 
• May have other symptoms including a low fever, bumps under the skin –called rheumatoid nodules – and anemia, a low red blood cell count 
• Is more common among young females than young males 

Systemic   

• Affects not only joints, but the whole body 
• Can cause inflammation of internal organs, such as the heart and lungs 
• May present with a high spiking fever that comes and goes and/or a pinkish rash on the chest and thighs – months before joint inflammation begins 

Enthesitis    

• Causes inflammation of the entheses – the spot where muscles and tendons attach to bones 
• Causes pain and swelling in specific joints and other areas of the body, including the heels, toes, fingers, elbows, pelvis and chest 
• Is more common among boys than girls 

Psoriatic 

• Causes joint inflammation as well as skin conditions   
• A scaly rash – behind the ears or on the eyelids, elbows, knees or scalp – may appear long before or after joint inflammation becomes a problem 
• Can also cause pitting and ridging on the fingernails 

Undifferentiated 

• Arthritis that lasts for at least six weeks, but doesn’t match any of these descriptions perfectly