Adult-onset Stills Disease: Advocating for New Markers to Overcome the Diagnostic Challenge

Adult-onset Still's disease (AOSD), is the adult form of systemic juvenile rheumatoid arthritis (juvenile Still's disease). AOSD is a known cause of fever of unknown origin (FUO). It is characterised by a triad of symptoms: spiking fever (>39°C), salmon-coloured rash and arthritis/arthralgia. However, rash is not easily appreciated in wheatish or dark colour patients as are seen in tropical countries. First described in 1971, it is a rare, difficult to diagnose, idiopathic, autoinflammatory, multisystemic disorder characterised by two subsets according to clinical and laboratory features: systemic or articular. Timely diagnosis and treatment of the disease can prevent complications and lead to a favourable prognosis. We present and discuss a young female patient who presented as FUO and was diagnosed timely as AOSD and treated with corticosteroids and had a desirable outcome and prognosis. We will also discuss the role of some potential biomarkers including procalcitonin and ferritin. Can these markers, along with other biomarkers, like IL 18, s100 proteins and sCD163 be included in diagnostic criteria of AOSD need further research, study and meta-analysis?