What Are the Types of RA?

Rheumatoid arthritis (RA) can be classified into several types based on its clinical presentation, disease activity, and response to treatment. Here are some common types of RA:

1. Seronegative RA: This type of RA is characterized by the absence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies in the blood. Seronegative RA accounts for approximately 10% to 20% of all RA cases.

2. Seropositive RA: This type of RA is characterized by the presence of RF and/or anti-CCP antibodies in the blood. Seropositive RA is more common than seronegative RA and accounts for approximately 80% to 90% of all RA cases.

3. Early RA: Early RA refers to the initial stage of the disease, typically within the first two years of symptom onset. It is characterized by joint pain, swelling, stiffness, and inflammation in the synovium (the lining of the joints). Early RA can be difficult to diagnose as the symptoms may be mild and intermittent.

4. Established RA: Established RA refers to the stage of the disease that occurs after the initial two years. It is characterized by persistent joint pain, swelling, and inflammation, as well as joint damage and deformity. Established RA may also affect other organs and systems in the body, leading to systemic symptoms such as fatigue, weight loss, and anemia.

5. Polyarticular RA: This type of RA affects multiple joints, typically involving the small joints of the hands, feet, and wrists. Polyarticular RA is the most common type of RA and can range from mild to severe in terms of disease activity.

6. Oligoarticular RA: This type of RA affects only a few joints, usually less than four. Oligoarticular RA is less common than polyarticular RA and often involves the larger joints, such as the knees, ankles, or elbows.

7. Symmetrical RA: This type of RA affects the joints on both sides of the body in a symmetrical pattern. For example, both hands or both knees may be affected. Symmetrical RA is more common in seropositive RA.

8. Erosive RA: This type of RA is characterized by the presence of erosions, which are areas of bone damage and destruction. Erosive RA is more common in seropositive RA and is associated with a higher risk of joint deformity and disability.

9. Non-erosive RA: This type of RA does not involve bone erosion and is typically less severe than erosive RA. Non-erosive RA is more common in seronegative RA and is associated with a lower risk of joint deformity and disability.

10. Juvenile idiopathic arthritis (JIA): This is a type of RA that affects children and adolescents under the age of 16. JIA can be further classified into several subtypes based on the age of onset, joint involvement, and associated features.

It's important to note that the classification of RA types can be complex and may vary depending on the specific criteria used by healthcare professionals. Additionally, the course of RA can vary significantly from person to person, and some individuals may experience different types or combinations of RA over time.