An Overview of Inflammatory Polyarthritis

Polyarthritis (also known as polyarticular arthritis or inflammatory polyarthritis) is defined as arthritis or joint pain that affects five or more joints simultaneously. The term itself simply describes the number of joints involved: poly means many. As such, it can be used to describe any number of conditions, permanent or transient, in which more than five joints are affected. Polyarthritis is most often associated with autoimmune diseases such as rheumatoid arthritis (RA), but can also be brought on by certain viral infections.

Symptoms

Symptoms of polyarthritis tend to be similar to those of rheumatoid arthritis and other autoimmune diseases. They can develop suddenly or over a period of many months.

Signs of joint inflammation are typically cardinal in nature, including swelling, warmth, pain, and decreased range of motion. Morning stiffness and pain that improves with activity and worsens with rest are classic presentations of inflammatory arthritis.

Other symptoms include:

• Rash
• Tiredness or a lack of energy
• Temperature of 100.4 degrees or above
• Swollen lymph nodes
• Sweating
• Lack of appetite
• Unexpected weight loss

Causes

Polyarthritis is most often caused by an autoimmune disorder, in which a person's immune system mistakenly attacks its own cells and tissues. The causes of autoimmune disease are not well understood but are believed to be strongly associated with genetics and environment.

Because autoimmune diseases tend to trigger an all-body response (they're systemic diseases with myriad symptoms), polyarticular joint involvement generally does not appear in isolation as it might with osteoarthritis. Rather, there are a host of other important symptoms (i.e. rash).

The autoimmune disorders most commonly associated with polyarthritis include:

• Rheumatoid arthritis
• Psoriatic arthritis
• Lupus
• Scleroderma
• Juvenile idiopathic arthritis
• Sarcoidosis
• Gout

Polyarthritis can also occur as part of an acute illness such as rheumatic fever, as well as certain alphaviral infections, including the Ross River virus, chikungunya virus, and Mayaro virus. Dengue, Zika, hepatitis, EBV and CMV may also cause polyarthritis. In these cases, the inflammation may be transient and migrate between multiple joints.

When polyarthritis occurs in children, it is called juvenile idiopathic arthritis or JIA; the cause is unknown.

Diagnosis

Because polyarthritis is most commonly associated with autoimmune diseases, your physician will typically start by trying to pinpoint the underlying reason for your joint pain. Inflamed joints, tenderness, joint effusion (known as water on the knee), and swelling are common signs of autoimmune diseases.

Your doctor will evaluate whether your pain is symmetric (symptoms are occurring in both hands or knees, for example) or asymmetric (just the joints on one side are symptomatic). People with RA tend to experience symmetric symptoms, while those with psoriatic arthritis often experience asymmetrical symptoms.

For RA specifically, two blood tests—the rheumatoid factor test and the anti-cyclic citrullinated peptide (anti-CCP) antibody test—can help confirm the diagnosis. Your doctor may also check for anemia, an elevated white blood cell count, elevated platelets, and increased inflammatory markers known as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Serology testing may also be helpful to look for specific antibodies related to the autoimmune disease in question.

Depending on the suspected cause, X-rays, a musculoskeletal ultrasound, magnetic resonance imaging (MRI), and/or a joint fluid analysis (also known as arthrocentesis) may be ordered. Your doctor will also test for viruses if an infectious cause is suspected.

Treatment

Treatments for polyarthritis are typically the same as for autoimmune diseases. They include:

• Non-steroidal anti-inflammatory drugs (NSAIDs): Advil (ibuprofen), Aleve (naproxen), and Voltaren (diclofenac) can help relieve pain and stiffness.
• Disease-modifying anti-rheumatic drugs (DMARDs): These help slow the course of autoimmune diseases. Methotrexate is frequently prescribed to reduce joint damage caused by polyarthritis.
• Biologics: These drugs, which include Remicade (infliximab) and Embrel (etanercept), modify the immune system to reduce inflammation.
• Corticosteroids: These help control inflammation and reduce pain. Steroids can be taken orally or via injection. They should only be used in the short-term, as they can cause serious side effects.
• Warming therapies: Warm baths, warming mitts, and over-the-counter topical creams such as Aspercreme can temporarily relieve symptoms.
• Exercise: Low-impact exercises like swimming, yoga, and stretching, can help keep joints healthy.

A Word From Verywell

It's important to treat polyarthritis before the condition worsens and causes permanent joint damage. In rare cases, polyarthritis can cause scarring in the lungs, dry eyes, skin rash, and pericarditis (inflammation in the sac surrounding the heart). If you experience pain in five or more joints, a call to your doctor is in order.