What autoimmune disease is known for painful swelling of the joints?

Rheumatoid arthritis is characterized by painful swelling of the joints due to an autoimmune response where the body's immune system mistakenly attacks the synovium—the lining of the membranes that surround the joints. This condition often leads to inflammation, redness, warmth, and swelling, typically affecting joints symmetrically on both sides of the body, such as the fingers, wrists, knees, and ankles.

In addition to joint pain, rheumatoid arthritis can also affect other systems in the body, such as the skin, eyes, lungs, heart, and blood vessels, leading to a wide range of symptoms beyond just joint discomfort. This systemic nature distinguishes rheumatoid arthritis from other joint-related diseases.

While osteoarthritis primarily results from wear and tear on the joints and is not classified as an autoimmune disease, gout is caused by the accumulation of uric acid crystals in the joints, leading to sudden and severe pain but is also not autoimmune in nature. Psoriatic arthritis, while also an autoimmune condition that causes joint inflammation and pain, typically occurs in patients with psoriasis and may present differently in terms of joint involvement and skin symptoms. Each of these conditions has distinct characteristics and mechanisms of action, but for the specific question of painful joint swelling due to an autoimmune process, rheumatoid arthritis is