Adult Onset Still’s Disease (AOSD)
What is Still’s Disease?
In 1896 George Still, a paediatrician, first described a condition which would later be called Still’s disease in children who developed swelling of the joints connected with a fever and sometimes a rash. This condition in children under 16 is now known as juvenile inflammatory polyarthritis.
Adults over 16 can also develop the same condition which is called Adult-Onset Still’s diseases or AOSD. AOSD is very rare, only developing in between 1 and 4 people in a million every year, and because it is so rare there is often a delay in making the diagnosis. Most people with AOSD will be between 16 and 35 when the condition starts.
AOSD is caused by an abnormality of the immune system which causes generalised inflammation. The cause of this, alongside most immune disorders is not known but it could be a combination of infectious or environmental causes triggered by a genetic tendency.
What are the symptoms of Still’s Disease?
Typical AOSD starts as stiff, painful inflamed joints, a temperature which peaks at the same time each day and what is called a “salmon-pink” rash often on the trunk and legs which also comes and goes with the spikes of temperature. Some people also develop a sore throat, aching, swollen glands or enlargement of the liver or spleen. Not everyone with AOSD develops swollen joints which can also make the diagnosis difficult as the symptoms can be confused with an infection or other types of rheumatological condition.
How is Still’s Disease diagnosed?
Most people with AOSD have abnormal blood tests including raised inflammatory markers (CRP and ESR), raised white cells in the blood, and most importantly very high levels of a substance called ferritin in the blood which often suggests the diagnosis.
What are the treatments for Still’s Disease?
Treatment of AOSD depends on the severity of the condition. Mild symptoms can be treated with non-steroidal anti-inflammatory drugs such as naproxen, but people with moderate-to severe disease will need some form of immunosuppression such as prednisolone to control inflammation and improve pain and function. Most people with more severe disease will be treated with a disease-modifying drug such as methotrexate, or biologic drugs given by injection such as anakinra (an interleukin-1 receptor antagonist) or rituximab (an anti-CD20 monoclonal antibody) to prevent long term joint and organ damage. Many people will be able to taper down and come off these medicines completely in time.
1 in 3 people will have a single episode of AOSD and will recover completely without the need for more treatment. About 1 in 3 people will have intermittent episodes and 1 in 3 will develop a more chronic form of the condition which is likely to need long-term immunosuppressive treatment usually with anakinra or rituximab.
How can I help myself?
Self-management of the symptoms of AOSD is important, as with any type of arthritis and include staying as active as possible, healthy eating and keeping to a healthy weight and working on emotional issues, mental health, social support and sleep.
Read more about self-management for arthritis.