A considerable proportion of patients presenting with early arthritis have a disease that cannot be classified directly; this is called undifferentiated arthritis (UA). UA patients are heterogeneous in several aspects. This is reflected by the diverse outcomes: one third of the patients progresses to rheumatoid arthritis (RA), one third remains unclassified and one third remits spontaneously. In this presentation the heterogeneity will be evaluated and questions that are relevant for clinical practice will be addressed. Which UA patients will progress towards RA in case untreated? What is the disease outcome? When should treatment be initiated?, What drugs to choose? This presentation is based on the currently available literature; the randomized clinical trials in UA will be explored to provide answers that are helpful for daily clinical care.
Disclosure of Interest None declared