How can you tell the difference between rheumatoid arthritis and psoriatic arthritis

If you’re dealing with unexplained, long-lasting joint pain, understanding the difference between psoriatic arthritis vs. rheumatoid arthritis is crucial. While they may sound very similar, these chronic conditions have some key distinctions when it comes to symptoms, causes, diagnosis, and treatment—all of which feed into the bigger picture of living with arthritis in general.

Both conditions are autoimmune diseases, meaning inflammation fuels most of the painful symptoms each type of arthritis is known for.1 Both conditions are also fairly common: Rheumatoid arthritis affects roughly 1.3 million people in the U.S., according to the National Library of Medicine (NLM), while experts at John Hopkins University estimate that 1.5 million people in the U.S. have psoriatic arthritis.

Despite this, getting answers isn’t so straightforward. People may deal with painful symptoms for a long time before their doctor lands on an accurate diagnosis. For example, in one small study of 200 people with psoriatic arthritis, 192 individuals said they were initially misdiagnosed.2 One of the reasons this happens is because psoriatic arthritis can manifest in different ways and in different areas of the body, making it hard to pinpoint.3

That’s why understanding the specific nuances of psoriatic arthritis versus rheumatoid arthritis is important—it can help you advocate for yourself during medical appointments if you think you have one of these common diseases. Here’s what you need to know.

What is psoriatic arthritis versus rheumatoid arthritis?

As we mentioned, rheumatoid arthritis is an autoimmune disease. But what does that mean exactly? Normally, your immune system is in the business of protecting you against potentially harmful germs like bacteria and viruses. In rheumatoid arthritis, your immune system goes a little haywire, according to the Centers for Disease Control and Prevention (CDC). It mistakenly attacks the tissues lining your joints, spurring the inflammation that is responsible for painful swelling and even joint deformity.

Psoriatic arthritis is also an autoimmune disease, meaning the immune system also becomes overzealous in this case and attacks healthy cells that it shouldn’t. However, many people with psoriatic arthritis also have psoriasis, meaning their immune system attacks their joints and skin, according to the NLM. In fact, psoriatic arthritis and psoriasis occur together so frequently that doctors sometimes group psoriatic arthritis and psoriasis together under the umbrella of psoriatic disease.3 According to the Cleveland Clinic, up to 30% of people with psoriasis also develop psoriatic arthritis.

“People with psoriatic arthritis tend to have the skin disease first, and then develop arthritis,” Cuoghi Edens, M.D., assistant professor at the University of Chicago’s Department of Internal Medicine and Pediatrics, tells SELF. But that’s not always the case and can make a clear diagnosis challenging. You can develop psoriatic arthritis even if you don’t have psoriasis and vice versa.

There are five types of psoriatic arthritis, and each can manifest in your body very differently, according to the NLM:

• Asymmetric oligoarticular can impact up to five joints, though not necessarily the same ones on each side of the body.
• Symmetric polyarthritis affects the same joints on each side of the body.
• Spondylitis primarily affects the spine, though other joints such as your arms and hands can be involved. With this type, you might have a lot of pain and stiffness in your back and neck.
• Distal interphalangeal predominant psoriatic arthritis mainly affects the joints closest to your fingernails and toenails. This can make it hard to grip objects or walk.
• Arthritis mutilans is the most severe form of psoriatic arthritis. It damages the joints in your hands and feet, making it exceptionally difficult to move.

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What are some psoriatic arthritis causes versus rheumatoid arthritis causes?

You may search through your family tree looking for a hereditary link to these conditions—but is rheumatoid arthritis genetic? What about psoriatic arthritis? We wish the answers were clearer: “There isn’t a single gene that we could test to determine if a person has psoriatic or rheumatoid arthritis, or that they will go on to develop those conditions,” Maureen Dubreuil, M.D., assistant professor of medicine at Boston University School of Medicine and rheumatologist at Boston Medical Center, tells SELF.

Although there isn’t a single rheumatoid arthritis gene, some people who were born with genes called human leukocyte antigens (HLA) are more likely to develop rheumatoid arthritis.4 The presence of these genes has also been linked to more severe symptoms, according to the CDC, although it’s not fully understood why. And while genes likely set the stage for rheumatoid arthritis, they don’t necessarily act alone. “There’s probably some genetic increased risk, and then some trigger causes the disease to become active,” Dr. Edens says. Possible environmental triggers include things like cigarette smoking and air pollution, and certain occupational hazards, research shows.5

Psoriatic arthritis causes are also murky, but genes are likely involved in it too. About 40% of people with this condition have at least one family member who has been diagnosed with it, according to the American College of Rheumatology. While there isn’t one psoriatic arthritis gene, those same HLA genes linked to rheumatoid arthritis may also increase psoriatic arthritis risk.6 As for what can trigger psoriatic arthritis? Psoriatic arthritis can also be triggered by environmental influences, such as cigarette smoking, high-stress situations, and infections such as strep throat.7

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Rheumatoid arthritis symptoms versus psoriatic arthritis symptoms

Rheumatoid arthritis tends to be a more symmetrical inflammatory disease, meaning the same joints on both sides of your body are likely to be affected. According to the CDC, you might experience the following symptoms of rheumatoid arthritis:

• Smaller joints may hurt first: Pay close attention to your wrists, fingers, and toes. As rheumatoid arthritis progresses, your larger joints can become affected.
• Pain and stiffness in the same joints: Tenderness and swelling can become worse when you move. For example, you may have pain in both of your knees or both of your wrists—not just one knee. Sometimes, your pain can be so severe that you have trouble tying your shoes, brushing your hair, or getting out of bed. You may feel especially stiff and in pain when you wake up.
• Firm lumps: These are called rheumatoid nodules, and they typically form around joints like your elbows, notes the Mayo Clinic, but can pop up anywhere in the body.
• Feeling especially tired or weak: This fatigue can get to the point where you need to nap midday or feel like you can’t function as you normally can.
• Fever: This can happen occasionally due to the body’s immune response.
• Unintentional weight loss: Experts theorize this happens because proteins called cytokines, which are involved with rheumatoid arthritis inflammation,8 may also affect your metabolism and cause your muscles to break down.9 You may also just have a hard time preparing your meals, so you may eat less than you normally would.

Similar to rheumatoid arthritis, psoriatic arthritis can affect the small joints in your hands or feet or the larger joints like your knees, shoulders, and hips. But you’ll also notice that there are some distinct psoriatic arthritis symptoms as well. “Psoriatic arthritis is more asymmetrical—so people will often have one ankle, one knee, or one wrist involved,” Dr. Edens explains.

However, this isn’t always the case, so this guideline isn’t foolproof. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, some other common psoriatic arthritis symptoms include:

• Joint pain, stiffness, or swelling: This affects one or multiple joints and often feels worse in the morning or after resting. You may have trouble taking care of yourself, walking, or gripping things, depending on the location of your affected joints.
• Pain or tenderness in entheses: These areas, where tendons or ligaments attach to your bones (like the back of your heel, soles of your feet, or elbows), can become inflamed and cause discomfort.
• Painful swelling in fingers and toes: This can cause them to look a bit sausage-like, and is known as dactylitis.
• Fatigue: Dealing with chronic pain can be exhausting, so everyday tasks can feel like a major struggle due to feelings of tiredness.
• Scaly, inflamed skin patches: These silvery, white, or gray plaques are characteristic of the most common type of psoriasis, and can present differently depending on your skin tone. They often show up on the scalp, elbows, or knees.
• Nail changes: This can include pitted or ridged nails that sometimes separate from your nail bed.

What’s more, both conditions can set their sights on more than just your joints. Chronic bodily inflammation can eventually affect other organs, increasing your risk of issues like inflammatory eye disease (which can lead to eye redness or pain, vision loss, or light sensitivity), inflammatory bowel disease like Crohn’s or ulcerative colitis, and cardiovascular disease.

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Rheumatoid arthritis diagnosis versus psoriatic arthritis diagnosis

Finding out the root cause of your symptoms is important to not only feeling better but also preventing long-lasting joint damage before it starts. If you’re able to, the Arthritis Foundation recommends seeing a doctor who specializes in treating inflammatory joint diseases, called a rheumatologist (your primary care doctor can give you a referral if needed). Your doctor should ask about your medical history, including your symptoms and whether anyone in your family has arthritis, psoriasis, or another autoimmune disease. Then your doctor will examine your body to look for joint swelling that can indicate either form of arthritis.

From there, if either condition is suspected, your doctor can check your blood for erythrocyte sedimentation rate (ESR or “sed rate”) and C-reactive protein (CRP), which are markers of bodily inflammation. These tests show that you have inflammation, but they don’t confirm the exact cause of it, Dr. Dubreuil says. Your doctor may also request a specific blood test to look for proteins called rheumatoid factor (RF) and cyclic citrullinated peptide (CCP), which are typically higher in people who have rheumatoid arthritis, according to the Mayo Clinic. This test can only indicate that you might have an autoimmune condition, as people can have higher levels of these proteins and not have an autoimmune condition.

Your doctor might also recommend an X-ray to look for bone, tendon, or ligament damage, but this is usually most helpful in a more developed disease. “In people whose joint pain or swelling started recently, we often don’t see anything on X-ray,” Dr. Dubreuil says. “Then we often move on to a more advanced technique.” That might include magnetic resonance imaging (MRI) or ultrasound to unveil possible swelling in the soft tissues.

For a psoriatic arthritis diagnosis specifically, you may also need to see a dermatologist to confirm if you also have signs of psoriasis, since the two conditions are so often intertwined. “The physical exam is very important to look for psoriasis in hidden areas and nail changes that might suggest psoriasis,” Dr. Dubreuil says. For example, changes in your nails can include pitting or your nails separating from your nail beds. 

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Rheumatoid arthritis treatment versus psoriatic arthritis treatment

Can rheumatoid arthritis go away? Can you reverse psoriatic arthritis? These are questions you may ask yourself at some point following your diagnosis and, unfortunately, the answer is there is no cure for either condition. However, you can absolutely feel better with treatment and feel more in control of your life. Regardless of your diagnosis, rheumatoid arthritis treatment and psoriatic arthritis treatment overlap quite a bit, because the goal is to get your inflammation under control and to prevent long-term joint damage. 

You may start by trying nonsteroidal anti-inflammatory drugs (NSAIDs) to tamp down inflammation, which drives the pain, tenderness, and swelling. Corticosteroids are another drug that suppresses inflammation and are commonly prescribed via oral medications or injection. Prescription medications called disease-modifying antirheumatic drugs (DMARDs) can also help slow the progression of either disease, according to the Mayo Clinic. If your symptoms don’t improve, then your doctor might switch you to a different type of DMARD or to a class of medications known as biologics, which are delivered via IV infusion or injection to help target the specific parts of your immune system involved in causing autoimmune conditions.

If you have psoriatic arthritis and psoriasis, then your treatment plan may vary slightly to help treat your skin symptoms too. This often includes topical versions of corticosteroids, retinoids, or immunosuppressive creams like calcineurin inhibitors.

It’s important to understand that there’s no one-size-fits-all approach to treating either disease, and how effective a particular medication is can vary from person to person, Ana-Maria Orbai, M.D., director of the psoriatic arthritis program at Johns Hopkins University School of Medicine, tells SELF. Plus, each medication comes with the risk of potential side effects. Weigh out the pros and cons of each option with your doctor to help strike the right balance for your long-term health.

Bottom line: To intervene early, you need an accurate diagnosis from your doctor—and that starts with recognizing symptoms that can be easy to miss. What’s more, dealing with the constant demands of work, family, and personal responsibilities can make it easy to ignore pain and swelling before they possibly become debilitating. “Ongoing joint pain and swelling are not normal,” Dr. Dubreuil stresses. “They warrant a check-in with your primary care provider.”

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Sources:

1. RMD Open, Distinguishing Rheumatoid Arthritis from Psoriatic Arthritis
2. BMC Rheumatology, Patient Perspectives on the Pathway to Psoriatic Arthritis Diagnosis
3. Scientific Reports, Psoriatic Disease is Associated with Systemic Inflammation, Endothelial Activation, and Altered Haemostatic Function
4. Rheumatic Disease Clinics of North America, HLA-Disease Associations in Rheumatoid Arthritis
5. Medical Principles and Practice, Rheumatoid Arthritis: A Brief Overview of the Treatment
6. Rheumatology, The Many Faces of Psoriatic Arthritis: Their Genetic Determinism
7. Indian Journal of Dermatology, Genetics of Psoriasis and Psoriatic Arthritis
8. Frontiers in Immunology, Macrophage Cytokines: Involvement in Immunity and Infectious Diseases
9. ACS Omega, Appraisal of the Antiarthritic Potential of Prazosin via Inhibition of Proinflammatory Cytokine TNF-α: A Key Player in Rheumatoid Arthritis

Related:

• Psoriatic Arthritis Medication: What You Need to Know
• How Biologics Can Improve Your Psoriatic Arthritis Symptoms
• 5 Ways to Manage Rheumatoid Arthritis at Work

How do I know if I have rheumatoid arthritis or psoriatic arthritis?

What are the six signs of psoriatic arthritis?

How does a doctor determine if you have psoriatic arthritis?

What does the beginning of psoriatic arthritis look like?