An Overview of Inflammatory Polyarthritis

Polyarthritis means five or more joints are affected by arthritis. It's most often associated with autoimmune diseases such as rheumatoid arthritis (RA), and certain viral infections can also trigger it.

If you're not already diagnosed with a condition that can lead to polyarthritis, your healthcare provider may use blood tests, imaging, and a physical exam to diagnose the underlying cause.

This article explains polyarthritis symptoms, causes, diagnosis, and treatment.

Symptoms

Polyarthritis symptoms tend to be similar to those of rheumatoid arthritis and other autoimmune diseases that affect the joints. They can develop suddenly or over many months.

Autoimmune diseases tend to trigger an all-body response because they're systemic diseases with varied symptoms. Therefore, joint involvement generally does not appear in isolation as it might with osteoarthritis (OA). Instead, there are many other symptoms, like a rash.

Other symptoms include:

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

In rare cases, the inflammatory disease that causes polyarthritis can also cause scarring in the lungs, dry eyes, skin rash, and pericarditis (inflammation in the sac surrounding the heart).

Causes

Polyarthritis may be caused by an autoimmune disorder or an acute illness. It occurs when the inflammation affects joints in the body. Symptoms can be constant or may flare up as the underlying inflammatory condition flares up.

Autoimmune Disorders

Polyarthritis is most often caused by autoimmune disorders. In autoimmune disorders, the immune system mistakenly attacks its cells and tissues. The causes of autoimmune diseases are not well understood but are strongly associated with genetics and the environment.

The autoimmune disorders most commonly associated with polyarthritis include:

• Gout
• Lupus
• Juvenile idiopathic arthritis
• Psoriatic arthritis
• Rheumatoid arthritis
• Sarcoidosis
• Scleroderma
• Sjogren's syndrome

Illness

Polyarthritis can also occur as part of an acute illness such as:

• Rheumatic fever
• Alphaviral infections, including the Ross River virus, chikungunya virus, and Mayaro virus
• Dengue
• Zika
• Hepatitis
• Epstein-Barr virus (EBV)
• Cytomegalovirus (CMV)

In these cases, the inflammation may move between multiple joints.

Diagnosis

Polyarthritis is most commonly associated with an underlying disease, so your healthcare provider will typically start with an evaluation to see if you have a systemic disorder. Inflamed joints, tenderness, joint effusion (known as water on the knee), and swelling are common signs of autoimmune diseases.

Symmetry vs. Asymmetry

Your healthcare provider 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. Those with psoriatic arthritis often experience asymmetric symptoms.

Blood Tests

Bloodwork may be necessary to help narrow down a diagnosis. Tests to screen for RA commonly include:

• Rheumatoid factor test
• Anti-cyclic citrullinated peptide (anti-CCP) antibody test

In addition, your healthcare provider may check your blood for:

• Anemia
• Elevated white blood cell count
• Elevated platelets
• Increased inflammatory markers, known as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)

Serology testing may also be helpful to look for antibodies related to specific autoimmune diseases. Your healthcare provider will also test for viruses if an infectious cause is suspected.

Imaging Tests

Depending on the suspected cause, X-rays, a musculoskeletal ultrasound, magnetic resonance imaging (MRI), and a joint fluid analysis (also known as arthrocentesis) may be helpful.

Treatment

Treatments for polyarthritis are typically the same as for autoimmune diseases. They include medications for pain and inflammation, drugs to inhibit disease progression, and at-home therapies.

Medication

Non-steroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen), Aleve (naproxen), and Voltaren (diclofenac) can help relieve pain and stiffness.

In addition, disease-modifying anti-rheumatic drugs (DMARDs) can help slow the course of autoimmune diseases. For example, healthcare providers frequently prescribe methotrexate to reduce joint damage caused by polyarthritis.

Biologics, including Remicade (infliximab) and Enbrel (etanercept), modify the immune system to reduce inflammation.

Corticosteroids help control inflammation and reduce pain. You can take steroids orally or via injection. They should only be used in the short term, as they can cause serious side effects.

Treatment for viral-associated polyarthritis is typically symptom-based, as this condition tends to resolve without treatment.

At-home Therapies

Warming therapies can temporarily relieve symptoms.

These include:

• Warm baths
• Warming mitts
• Over-the-counter (OTC) topical creams such as Aspercreme

In addition, don't underestimate the value of exercise in managing polyarthritis. Low-impact activities like swimming, yoga, and stretching, can help keep joints healthy.

Summary

Polyarthritis is arthritis that affects five or more joints. Joint pain and inflammation are the most common symptoms, and symptoms may also include rash, fever, and fatigue. It is most commonly caused by an autoimmune disorder but can also be triggered by an acute infection. Treatment involves medication, at-home comfort measures, and exercise to keep joints flexible.

A Word From Verywell

It's essential to get a diagnosis and treatment for polyarthritis before the condition worsens and causes permanent joint damage. If you experience joint pain, call your healthcare provider.