Still's Disease, Adult-Onset

Adult Onset Still Disease (AOSD) and Systemic onset Juvenile Idiopathic Arthritis (SoJIA) are two rare multifactorial diseases associated with systemic inflammation. These two forms AOSD and SoJIA are considered to be two facets of the same syndrome, combining four cardinal symptoms \[hectic fever\> 39 °, arthralgia or arthritis, skin rash, a leukocyte formula with more than 80% of neutrophils\]; lymphadenopathy and splenomegaly may also be found. There is an important biological inflammatory syndrome with elevation of the reactive C protein, of serum ferritin with a dramatic drop in the glycosylated fraction. The incidence of the disease is low, around 0.1/100,000 for adults and 0.6/100,000 for children. Its prevalence is approximately 1 to 3/100,000 and 3/100,000 for children, so there are approximately 500 to 1,500 adults and 450 children affected in France. It is subdivided into pediatric and adult forms according to the age of onset before or after 16 years. The prognosis of the disease is functional and vital. Macrophage activation syndrome (SAM) is frequently associated with either the onset of the disease or the initiation of treatment or concomitantly with viral reactivati