Pain in arthritis

Under the term arthritis are grouped a large number of diseases characterized by the occurrence of an inflammatory process within the joints; between the different types of chronic arthritis, rheumatoid arthritis (RA) is the prototypical example. With the increasing importance of early diagnosis and treatment, in the last years several subsets of chronic arthritis have been described, starting from the early arthritis (EAs), term that include all the arthritis of recent onset; within the EAs we recognize the undifferentiated polyarthritis (UPA), that does not fulfill the classification criteria for an established chronic arthritis but that can turn into an established form of chronic arthritis overtime, and the early RA (ERAs), e.g., the arthritis of less than one year of duration fulfilling the ACR classification criteria for RA. Independently to the diagnosis, pain is a very common finding in this setting, deeply affecting patients' quality of life and generally representing the first symptom of the disease and the reason of medical referral. Moreover, pain expression in chronic arthritis is not univocal, being influenced by several factors; in this paper we analyze the different aspects and the role of pain in chronic arthritis like (E)RA and UPA.