What to Know About Inflammatory Polyarthritis

Polyarthritis means that five or more joints in your body are affected by arthritis and inflammation. It's most often associated with autoimmune diseases such as rheumatoid arthritis (RA), but some 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 are similar to those of rheumatoid arthritis and other autoimmune diseases that affect the joints. They can come on suddenly or over many months.

There are different kinds of inflammatory arthritis and it comes down to which joints are affected and how many joints are affected. In oligoarthritis, four or fewer joints are affected. If five or more joints are affected, it’s called polyarthritis.

Autoimmune diseases can trigger an all-body response because they're systemic diseases that can cause various symptoms. Joint involvement generally does not appear on its own as it can with “wear and tear” arthritis that comes with aging (osteoarthritis). 

Autoimmune causes of arthritis tend to have other symptoms including:

• Lack of appetite
• Rash
• Sweating
• Swollen lymph nodes
• A 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 inflammation in the sac surrounding the heart (pericarditis).

Causes

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

While there are some lifestyle strategies that can help keep your joints healthy as you age, you can’t always prevent a cause of inflammatory arthritis since conditions like autoimmune diseases are often linked to your genes.

Autoimmune Disorders

Polyarthritis is most often caused by autoimmune disorders. In these disorders, the immune system mistakenly attacks its cells and tissues. The causes of autoimmune diseases are not well understood but genetics and the environment are thought to play a major role.

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. In these cases, the inflammation may move between more than one joint.

Illnesses linked to polyarthritis include:

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

Diagnosis

Polyarthritis is most commonly related to an underlying disease. Your healthcare provider will ask you if you have other signs and symptoms along with inflamed joints like tenderness, joint effusion (known as “water on the knee”), and swelling, which are common signs of autoimmune diseases.

Symmetry vs. Asymmetry

Your provider will ask whether your pain is symmetric or on both sides (for example, in both hands or knees) or asymmetric, meaning it’s just on one side (one hand).

People with RA tend to have symmetric symptoms. Those with psoriatic arthritis often have asymmetric symptoms.

Blood Tests

Bloodwork can help your provider 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)

Other tests can help your provider look for antibodies related to specific autoimmune diseases (serology). Your provider can also test you for viruses if they think your symptoms could be related to an infection.

Imaging Tests

Depending on the possible cause, X-rays, a musculoskeletal ultrasound, magnetic resonance imaging (MRI), and a joint fluid analysis (arthrocentesis) can help your provider make a diagnosis.

Treatment

The treatments for polyarthritis are typically the same as for the autoimmune diseases that can bring it about. 

Your provider might recommend medications for pain and inflammation, drugs that can slow or stop the progression of the disease, and at-home therapies to help you manage your symptoms.

Medication

There are many medications that can help with symptoms of polyarthritis, depending on what the cause is.

Over-the-Counter

Non-steroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen), Aleve (naproxen), and Voltaren (diclofenac) can help relieve pain and stiffness. These are available over-the-counter (OTC) with a prescription. Your provider might also prescribe a higher dose if you need it.

OTC options can be used for polyarthritis from a viral illness because while they won't help with the infection, they can help with your symptoms until you're better.

Prescription

If you need more treatment than OTC medications, your provider might recommend some prescription medications.

One example of a prescription treatment your provider might want you to try for polyarthritis is disease-modifying anti-rheumatic drugs (DMARDs). These medications help slow the course of autoimmune diseases. For example, providers may prescribe methotrexate to reduce joint damage caused by polyarthritis.

Biologics, including Remicade (infliximab) and Enbrel (etanercept), are other treatments your provider might recommend. They change the immune system to reduce inflammation.

Corticosteroids control inflammation and can help with pain. You can take steroids orally or by injection. However, they should only be used in the short term because they can cause serious side effects.

At-Home Therapies

Warming therapies you can do at home can temporarily relieve symptoms of polyarthritis. Examples include:

• Warm baths
• Warming mitts
• OTC topical creams with a warming effect (e.g., Aspercreme)

Do not underestimate the value of exercise in managing polyarthritis symptoms. Low-impact activities like swimming, yoga, and stretching, can help keep your joints healthy.

Summary

Polyarthritis is arthritis that affects five or more joints. Joint pain and inflammation are the most common symptoms, but you can also have rash, fever, and fatigue depending on the underlying cause. 

Polyarthritis most commonly caused by an autoimmune disorder but can also be triggered by an acute infection. The treatment involves medication, at-home strategies to manage your symptoms, and exercise to keep your joints flexible.

You need to see your provider for a proper diagnosis and treatment for polyarthritis. The sooner the better, as you want to prevent the condition from getting worse and causing permanent joint damage