“Doctor, I have joint pain, do I have rheumatism?” “Am I rheumatic or rheumatoid?” “They say rheumatoid arthritis affects the heart, will my heart break down?” This is the most common question rheumatologists are asked. Rheumatism, rheumatoid, gout, arthritis …… is like a tangled mess of twine. The rheumatologists who face these questions every day can only silently raise their eyes to the sky, except for the thousand and one explanations. What are the rheumatic diseases? The rheumatology specialty is called rheumatic diseases, which refers to a group of diseases affecting bones, joints and their surrounding soft tissues such as muscles, tendons, synovial membranes, fascia, nerves and so on. The most commonly mentioned category is diffuse connective tissue disease (CTD), which is a non-organ-specific autoimmune disease. Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are both members under the CTD umbrella, while ankylosing spondylitis (AS) belongs to the category of spondyloarthropathies. Osteoarthritis (OA), which is common in the elderly, is a representative of degenerative changes; gout, or pseudogout, is related to metabolism and endocrine; rheumatic fever is an infection-related rheumatic disease. The “butterfly” and “moth” are not a family, rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, rheumatic fever, gout, although they all have arthritic manifestations, but the root is not the same thing at all. What is rheumatic fever? Rheumatic fever (RF) is an acute or chronic systemic connective tissue inflammation that recurs after infection of the throat with group A, type B, hemolytic streptococcus. Its 5 major manifestations are: wandering polyarthritis (more common in large joints), carditis, subcutaneous nodules, erythema annulare, and chorea. These manifestations can occur singly or in combination and have many subtypes. During the long years of lack of antibiotic treatment, the consequences of infection were unpredictable. A small sore throat and tonsillitis followed by what could be rheumatic fever and heart valve disease. The arthritis of rheumatic fever does not leave joint deformities and is not terrible, but heart valve disease severely impairs the patient’s ability to work and life expectancy. By the mid-20th century, with the common application of antibiotics, the incidence of rheumatic fever dropped significantly in countries around the world. By the 1980s, rheumatic fever was also rare in China. However, in the past 20 years, the incidence of rheumatic fever has picked up again, and its epidemiological pattern is changing. For this disease, the removal of streptococcal infection foci this etiological treatment is the most important, currently recognized benzathine penicillin is the drug of choice. What is the “holy grail” of rheumatoid arthritis? Rheumatoid arthritis (RA) is a connective tissue disease of unknown etiology characterized by chronic, symmetric, aggressive small arthritis, often associated with extra-articular organ involvement and positive serum rheumatoid factor (RF), CCP antibodies, etc. The most important pathological mechanism of RA is the formation of subcutaneous vascular opacities in the inflammatory state and the erosion and destruction of cartilage and bone, which often results in joint deformity and disability. The most important pathological mechanism of RA is the formation of subchondral opacities in the inflammatory state and their erosive destruction of cartilage and bone. The most common clinical manifestations of RA are morning stiffness, swelling and pain in the wrist, metacarpophalangeal and proximal interphalangeal joints, and joint destruction and deformity. The pathology of RA mainly consists of synovial lining cell proliferation, massive interstitial inflammatory cell infiltration, and microvascular neogenesis, formation of vascular opacities and destruction of cartilage and bone tissue. At this point, I think we all understand why “rheumatic fever” and “rheumatoid arthritis” are so easily confused. Rheumatoid arthritis, an informal term derived from rheumatic fever, has left a deep imprint on people’s memories for thousands of years, even after the disease has been gradually withdrawn from our sight for 30 years, it still has a place in the name of the disease. It is not surprising that the abbreviation RF is identical to the signature rheumatoid factor (RF) abbreviation of RA, which has caused confusion. Perhaps, with the passage of time, this confusion will eventually be forgotten.