Arthritis is a general term that refers to inflammation of the joints. There are more than 100 different types of arthritis, each with its own causes and treatments, but the two most common types are osteoarthritis and rheumatoid arthritis.

1. Osteoarthritis: This is the most common form of arthritis, often called wear-and-tear arthritis. It occurs when the protective cartilage that cushions the ends of your bones wears down over time. Osteoarthritis can affect any joint but commonly affects the knees, hips, hands, and spine. It typically develops gradually and can cause pain, stiffness, and swelling in the affected joints.

2. Rheumatoid arthritis: Unlike osteoarthritis, which is caused by wear and tear on the joints, rheumatoid arthritis is an autoimmune disorder. It occurs when the immune system mistakenly attacks the synovium, the lining of the membranes that surround the joints. This causes inflammation that can damage the cartilage and bone within the joint. Rheumatoid arthritis commonly affects the hands, wrists, and knees and can cause pain, swelling, stiffness, and deformity of the joints.

Other types of arthritis include gout, lupus, psoriatic arthritis, and ankylosing spondylitis, among others. While the specific symptoms and treatments vary depending on the type of arthritis, common treatments for arthritis include medication, physical therapy, lifestyle changes, and in some cases, surgery. Early diagnosis and treatment are important for managing symptoms and preventing joint damage.