Inflammatory Arthritis

Inflammatory arthritis, which includes conditions such as rheumatoid arthritis and gout, can be painful and debilitating.

What is inflammatory arthritis?

Inflammatory arthritis is joint inflammation caused by an overactive immune system. It usually affects many joints throughout the body at the same time but could involve just one joint. Inflammatory forms of arthritis are much less common than osteoarthritis, which is the most common type of arthritis. Although there are many exceptions, inflammatory arthritis generally starts earlier in life, and osteoarthritis later in life.

What is the difference between osteoarthritis and inflammatory arthritis?

The major distinction between is the processes that underlie these two diseases, which can have similar symptoms. Osteoarthritis starts in the cartilage, the shock absorber that lines the bone at the joints. Inflammatory arthritis often begins in other soft tissues that line the joint. Osteoarthritis is less of an inflammatory process, although inflammation is still present.

Osteoarthritis

It used to be thought that osteoarthritis was just a “wear-and-tear” process over time, but it is much more complicated than that. Osteoarthritis starts in the articular cartilage, which lines the bone at the joints to allow them to glide smoothly together. This cartilage gets damaged, and the underlying bone becomes thickened and forms spurs (osteophytes). The ligaments of the joint are also involved. Factors that contribute to osteoarthritis are aging, joint injury, genetics, body weight, and other mechanical factors that affect how a person’s joints are aligned.

Inflammatory arthritis

Inflammatory arthritis is caused by different joint processes from those in osteoarthritis. The most common inflammatory arthritis, rheumatoid arthritis, starts in the lining tissue of the joint, called the synovium. Immune cells come into this tissue causing the lining to thicken. These immune cells, as well as the cells normally found in the lining, release chemicals that cause the signs of inflammation: swelling, redness and heat.

In rheumatoid arthritis, multiple joints are often involved at the same time, and often in a symmetrical pattern. This is also true of the inflammatory arthritis seen in lupus. In some kinds of inflammatory arthritis, this joint lining inflammation has a known cause, such as an infection, but in most cases the specific cause is not known.

In gout, a type of inflammatory arthritis that often attacks just one joint at a time, the cause is known: The body is reacting to uric acid crystals in the joint that develop due to an excess of uric acid. Pseudogout (a condition with gout-like symptoms but due to a different type of crystals) can involve one or many joints, and it also has a clear cause. Pseudogout results from the body developing an inflammatory reaction to deposits of calcium crystals.

Genetics plays a large part in determining who will get inflammatory arthritis. Inflammatory arthritis diseases can be diagnosed in patients as young as age 20 or 30. Children and teens may be diagnosed with a form of juvenile arthritis. Inflammatory arthritis is more common in females than in males, and ongoing studies are searching for reasons for this.

What are the symptoms of inflammatory arthritis?

The most common symptoms of inflammatory arthritis are:

• Joint pain and stiffness after periods of rest or inactivity, particularly in the morning.
• Swelling, redness and/or a feeling of warmth in the affected joints.

People with inflammatory arthritis generally experience waxing and waning symptoms where the patient can have alternating periods of "flares" of highly intense symptoms with periods of inactivity. Unfortunately, some people have continuous joint inflammation unless treatment is started.

In some types of inflammatory arthritis, there is inflammation in other parts of the body, such as the skin, lungs, blood vessels or eyes. In addition to being important considerations in determining treatment, these other symptoms can be clues as to what type of inflammatory arthritis a patient has.

What are the different types of inflammatory arthritis?

The major types of inflammatory arthritis include:

• rheumatoid arthritis
• psoriatic arthritis
• ankylosing spondylitis
• gout and pseudogout
• arthritis associated with connective tissue disease (lupus, myositis, Sjogren’s syndrome and scleroderma )
• infection-associated arthritis (Lyme disease, rheumatic fever, reactive arthritis)

The Early Arthritis Initiative of the Inflammatory Arthritis Center provides education and support groups for patients with inflammatory arthritis, both early in the course and for those with ongoing joint issues. HSS also offers specialized patient support and education programs for conditions such as lupus and rheumatoid arthritis.

How is inflammatory arthritis treated?

The goals of treatment are to get rid of joint pain and prevent permanent joint damage. When detected and treated in its early stages, the effects of inflammatory arthritis can be greatly diminished, or the condition may even disappear completely. If a person’s inflammatory arthritis has been active for a long time, it can sometimes be more difficult to control.  The importance of proper diagnosis, particularly in the early stages of the disease, may prevent serious, lifelong arthritic complications.

Several options are available to treat inflammatory arthritis, and these depend on the type of inflammatory arthritis. For people with rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis, they almost always need a “disease-modifying” medication. These medications have been shown in clinical trials to not only help with joint pain, stiffness and swelling, but have also been shown to stop joint damage. For arthritis associated with lupus, myositis or scleroderma, multiple medications are available, and picking the right one involves determining what other parts of the body are involved. For Lyme disease, antibiotic therapy is needed. For gout and pseudogout, anti-inflammatory agents such as ibuprofen and naproxen and be used, as well as colchicine and short courses of steroids. For gout, we have medications such as allopurinol that can stop the disease by lowering the uric acid level.

For all of the types of inflammatory arthritis, definitive treatment often takes time to work. While patients are getting started on disease modifying therapy, pain and swelling can be treated with non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen, taking into consideration any other medical conditions the person might have. In some cases, oral steroids (such as prednisone) are used to “cool down” inflammation. These are stronger anti-inflammatories than NSAIDs and require a prescription. Steroids are also sometimes given as local injections into a specific joint.  Physical therapy and splinting can be helpful along with disease modifying medications to help people return to their normal level of activity.

Medications for inflammatory arthritis

Disease-modifying antirheumatic drugs (DMARDs) have transformed the landscape of care for rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and arthritis due to other autoimmune diseases. These medications relieve inflammation and pain in people with inflammatory arthritis and, as their name implies, can actually change the course of the illness to prevent permanent joint damage.

Traditional DMARDs

This category includes methotrexate, hydroxychloroquine, sulfasalazine, and leflunomide. These medications are pills taken orally (by mouth), although methotrexate is also available as an injection. They are sometimes used alone, but for many patients they are not enough to adequately control the disease by themselves and are used in combination with a targeted or biologic DMARD (described below) or in combination with each other.

Biologic DMARDs

These medications differ from traditional DMARDs because they target specific proteins fueling the symptoms and damage of inflammatory arthritis. There are many types of biologic DMARDs, which inhibit different targets in the immune system. These medications cannot be taken orally and are given as a subcutaneous (under the skin) injection or intravenously (by vein). The subcutaneous injections are usually done at home. Biosimilar DMARDs are medications that have very similar effects as biologic DMARDs but may be available at a lower cost. These medications are grouped according to the proteins that they target:

• Tumor necrosis factor (TNF) inhibitors. TNF causes inflammation in multiple types of inflammatory arthritis. TNF inhibitors include adalimumab, infliximab, etanercept, golimumab, and certolizumab pegol.
• Interleukin-6 (IL-6) inhibitors. IL-6 is involved in inflammation of the joints in rheumatoid arthritis. IL-6 inhibitors include tocilizumab and sarilumab.
• IL-17 inhibitors and IL-12/23 inhibitors. These medications are useful in the treatment of psoriatic arthritis and ankylosing spondylitis. They include secukinumab, ixekizumab, and ustekinumab.
• Rituximab. This medication works by depleting B cells – white blood cells that play a role in the immune response and are involved in the formation of autoantibodies. This medication is effective in rheumatoid arthritis as well as other autoimmune diseases such as vasculitis.
• Abatacept. This medication interferes with the function of certain immune cells, called T cells, which are involved in inflammation in rheumatoid arthritis and psoriatic arthritis.
• IL-1 inhibitors. These include anakinra and canakinumab and are used in gout and other inflammatory diseases such as adult-onset still’s disease and familial mediterranean fever.

Targeted DMARDs (JAK inhibitors)

This group of medications are targeted inhibitors of Janus kinases (JAK) proteins, which are important for multiple types of inflammation. JAK inhibitors include baricitinib, tofacitinib, and upadacitinib. These medications are taken orally.

Surgery for inflammatory arthritis

As with osteoarthritis, joint replacement surgery may need to be considered when these nonsurgical methods have failed to provide lasting benefit. Of the types of inflammatory arthritis, rheumatoid arthritis is one of those most likely to lead to joint replacement. Fortunately, the number of disease-modifying agents for rheumatoid arthritis has dramatically increased and treatment is more effective than it once was.  The progress in treatment of rheumatoid arthritis has been quite dramatic over the decades since the late 1990s.

Learn more about inflammatory arthritis from the articles below or find a doctor at HSS who treats inflammatory arthritis.

Updated: 10/21/2024

Reviewed and updated by Melanie H. Smith, MD, PhD