The two main types of rheumatoid arthritis (RA) are seropositive and seronegative RA, with juvenile RA being another type that only affects children.

RA is an autoimmune disease that causes inflammation in the joints and may affect other parts of the body as well. It is a chronic, progressive condition that has the potential to seriously damage the affected joints. Every year, 41 of 100,000 people are diagnosed with RA.1

How Is RA diagnosed?

The diagnosis of RA includes blood tests: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), and anti-cyclic citrullinated peptide (anti-CCP) antibodies.

 Rheumatoid Arthritis: Blood Tests for Diagnosis

Bluecinema / Getty Images 

Seropositive RA

A seropositive RA diagnosis refers to positive anti-CCP and/or RF blood tests. Anti-CCP is used to identify antibodies that attack the body’s healthy cells, which results in inflammation.

The symptoms are lifelong and can improve or flare up at times, causing joint swelling, pain, and stiffness. Multiple joints will be involved, and they’re usually affected symmetrically (for example, both knees are usually affected instead of just one).

Seropositive RA is considered to be more progressive and severe than seronegative RA.2 Seropositive RA is associated with more joint damage, deformity, rheumatoid nodules, development of vasculitis, lung issues, and extra-articular manifestations.

Seronegative RA

Seronegative RA, in which anti-CCP and RA are absent, is less common than the seropositive type. In an early 2000 study, 12 out of every 100,000 RA patients were seronegative, and this number increased to 20 per 100,000 years later.3

This type of RA causes the classic RA symptoms, but they are often less severe and can be unpredictable. The diagnosis of seronegative RA is based on signs and symptoms of the condition, including morning stiffness, joint stiffness, swelling, pain, and symmetrical involvement of multiple joints.

Like seropositive RA, systemic symptoms are common, such as fever and fatigue. Rheumatoid nodules, vasculitis, and lung issues are less likely in seronegative RA.4

Juvenile RA

Juvenile RA, often referred to as juvenile idiopathic arthritis (JIA), is a form of RA that affects children aged 16 and under.

While kids often have growing pains, the pain, stiffness, and swelling of JIA are signs of disease and require treatment. Children with JIA may also have fevers, rash, and swollen lymph nodes.

The goal of JIA treatment is to control inflammation and pain to help keep the child active and social. Treatments for JIA include medications and therapy. In some situations, surgery may be warranted.

Autoimmune Comorbidities

RA is associated with multiple comorbidities, which tend to be other autoimmune diseases.5

The most common comorbidities seen with RA include:

Lupus

Diabetes

Thyroiditis

Sometimes the management of RA can decrease autoimmune disease activity and may result in an overall improvement across diseases.

 What Are the Risks of Untreated Rheumatoid Arthritis?

Conditions Often Confused with RA

There are many conditions that can be confused with RA due to similar symptoms. Some of these conditions are autoimmune, like RA, and some aren’t.

Conditions most often confused for RA include:

Fibromyalgia

Chronic fatigue syndrome

Anemia

Sciatica

Lyme disease

Neuropathy

Psoriatic arthritis

Studies show that there is often a lag in RA diagnosis after the initial symptoms start.6 It’s also possible to have a misdiagnosis before the more noticeable, serious symptoms of RA arise. 

A Word From Verywell

RA is a serious, lifelong disease, but with the right treatment, you can maintain a good quality of life. Keeping track of your own symptoms and flares can help you and your healthcare provider determine how well your medication is working. While knowing your RA type won’t necessarily change your treatment, understanding the different types can help guide your expectations.