Rhupus: dual rheumatic disease.

Autoimmune disorders are typically categorized into systematic and local diseases that affect a single organ or tissue. Organs and tissues affected by autoimmune disorders include components of the endocrine system, such as thyroid, pancreas, and adrenal glands; blood, such as red blood cells; and the connective tissues, skin, muscles, and joints. Rhupus is a complex musculoskeletal autoimmune disease (AD) in which features of both rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are simultaneously present. The cause and trigger of rhupus is still unknown, suggesting the role of genetic, immunological, hormonal, and environmental factors in the initiation and progression of the disease. The role of immune system has been established by the presence of specific autoantibodies as markers for diagnosis of rhupus and the formation of immune complex in serum. The complications of rhupus include the presence of rheumatoid factor (RF) and nodules and the involvement of nervous and renal systems that complicates its diagnosis and prognosis. The rhupus arthritis resembles RA-like pathophysiology and leads to inflammation, deformation, and disability. Due to the heterogeneity and rarity of the disease, the prevalence, pathophysiology, and natural history as well as radiological and immunological profiles of rhupus are still not properly understood.