Lupus Arthritis: What We Know and What Remains Unknown?

Joint manifestations constitute one of the characteristic clinical features observed in patients with systemic lupus erythematosus (SLE). Nevertheless, there is currently insufficient data and a lack of consensus regarding its pathogenesis, classification, treatment, and prognosis. Lupus arthritis (LA) is classically categorized into three forms: non-erosive and non-deforming type, non-erosive but deforming type (Jaccoud’s arthropathy; JA), and rheumatoid-like erosive arthritis (Rhupus syndrome; RS). However, recent advances in imaging modalities have notably revealed the presence of erosions even in non-erosive subtypes of LA. Another important question is whether rhupus cases represent a true overlap syndrome with rheumatoid arthritis (RA). Therefore, there is an absolute need for more data to establish a reliable classification of LA. Apart from classification, another major issue in lupus arthritis is treatment. In rheumatology practice, the efficacy and safety of both conventional synthetic and targeted disease-modifying agents in the management of inflammatory arthritis have been demonstrated through randomized controlled trials. Unfortunately, such data are not available for the treatment of LA. The current evidence is limited to expert opinions, case series, and a few clinical studies. The main reason for this is that SLE is not solely a joint disease but rather a systemic condition; it can involve nearly all organs and systems of the human body. In addition, in cases of RS, the likely coexistence of RA effectively doubles the number of diseases requiring treatment. In this chapter, we aimed to review all these issues from a broad perspective.