Rheumatoid Arthritis vs. Psoriatic Arthritis: Same Disease, Different Name?

Arthritis, in general, is related to joint pain and damage. There are many different types of arthritis, affecting many different joints in the body. While each type of arthritis has parallel clinical symptoms like joint pain, the causes and treatments are different.

Here, we will discuss two of the most common forms of arthritis: Rheumatoid Arthritis (RA) and Psoriatic Arthritis (PsA). At first glance, these two types of arthritis are very hard to differentiate, because they share so many overlapping traits. In fact, without the presence of a skin rash (i.e., psoriasis) in many cases of psoriatic arthritis, most people would not be able to tell a difference at first glance.

 

What is PsA?

PsA is an autoimmune disease that affects up to 30% of the population who live with psoriasis. In the overwhelming majority of diagnosed cases of PsA, individuals have a previous and chronic history of psoriasis. PsA occurs about equally in both men and women, with an average age of onset between 40 and 50 years old.
joint pain

PsA is chronic, and no cure is available at this time. Inflamed and painful joints are not the only thing affected by this disease. PsA can also damage your organs – such as your heart, lungs, and eyes. Osteoporosis (weakening of the bones) and tendonitis are also related side effects of this type of arthritis.

PsA is thought to occur in about one percent of the population.

1%
1% of the Population with Psoriatic Arthritis

 

What is RA?

RA is also an autoimmune disorder, where the body mistakenly attacks healthy joints. This attack on the joints leads to inflammation which leads to thickening of the tissues (synovium) lining the joints. In normal conditions, the synovium provides a lubricant to the joints to help them move smoothly. When the synovium thickens, this leads to friction, which causes swelling and pain.

wrist pain

RA is considered a systemic disease, meaning it affects the entire body. While it primarily affects the joints, RA can cause secondary conditions, damaging the organs and weakening the bones, similar to PsA.

RA is three times more prevalent in women than in men. The onset of the disease typically occurs between 30 and 60; though, the onset in men is later than in women.

RA affects approximately 1.5 million Americans.

 

What are the Symptoms of PsA?

Beyond the classic symptoms of arthritis, including painful and swollen joints, PsA presents itself with a number of symptoms. If you are living with PsA, you may have one or several of these symptoms during flare-ups. Additionally, the presence of psoriasis is also a classic symptom of PsA. Though, in a small percentage of individuals who live with PsA, no symptoms of psoriasis appear at all. In the overwhelming majority of cases, even if no psoriasis is present, there is a family history of it.

Some of the more common symptoms of PsA include:

  • Joint pain and inflammation
  • Joint stiffness – especially after prolonged periods of rest
  • Sausage-like fingers and toes (i.e., dactylitis)
  • Fatigue
  • Skin rashes
  • Nail pitting and other changes to the nail bed
  • Joint redness and warmth
  • Tendon and ligament pain
  • Reduced joint range of motion
  • Eye problems – including disturbed vision, irritability, redness, and pain
  • Flare-ups (i.e., symptoms come and go)
  • Metabolic syndrome (affecting weight, blood pressure, and cholesterol levels)
  • Related bone conditions (e.g., osteoporosis)
  • Depression (resulting from chronic pain)
  • Foot pain
  • Lower back pain

 

What are the Symptoms of RA?

Many of the symptoms of RA mirror those of PsA. Which is why oftentimes, the presence of psoriasis is a distinguishing factor in what type of arthritis you might be diagnosed with. Flare-ups are also common during RA – where the symptoms wax and wane. You might experience time periods of minimal symptoms and times when symptoms “flare-up.” In both RA and PsA, it is important to try to pinpoint what causes flare-ups. If you can determine underlying factors of the flare-ups (e.g., lack of sleep or increased mental stress), you might be able to minimize the presence of these symptoms. As with PsA, the following are RA symptoms that you may or may not have. You might only experience one or two of these symptoms or you might experience more.

Some of the more common symptoms of RA include:

  • Joint stiffness
  • Swelling, pain, and inflammation in the joints
  • Fatigue
  • Joint redness and warmth
  • Decreased joint range of motion
  • Anemia
  • Related bone issues (e.g., osteoporosis)
  • Low-grade fever
  • Numbness and tingling
  • Eye problems (red, itchy eyes)
  • Metabolic syndrome (increased blood sugar, blood pressure, and cholesterol)
  • Skin nodules

 

 

Similarities and Differences

As you can see, the overwhelming majority of symptoms between PsA and RA are the same or very similar. This often leads to understandable confusion among individuals trying to figure out if they are living with PsA or RA. Both are autoimmune disorders. Both affect similar organs. Both have similar related conditions (e.g., depression, metabolic syndrome). Both even are treated similarly. We have seen many similarities between the two types of arthritis. So, what are the differences?

knee pain

Many of the differences between the two diseases are only seen on a microscopic level. For one, individuals living with RA have rheumatoid factor (RF) present in their bloodstream. RF is an antibody and is not seen in PsA patients. On the other hand, PsA patients often have the presence of the HLA-B27 genotype.

Another difference between RA and PsA is what joints are affected and where. Typically, in RA, the same joints on both sides of the body are affected (e.g., the wrists on both sides of the body). With PsA, there are types where the joints are affected on both sides of the body, but typically there are more cases of joints being affected on only one side of the body.

PsA also tends to affect the more distal joints (those closest to the nail bed) in both the fingers and toes, whereas RA affects the first and middle joints of the fingers and toes. PsA often presents inflamed joints in the lower back and foot, whereas RA more commonly affects the wrists and the digits.

lower back pain

PsA causes a condition known as dactylitis, which makes the fingers and the toes look “sausage-like.” In essence, the entire finger and entire toe becomes inflamed and swollen. In contrast, swelling normally only appears in the affected joint (e.g., first or second joint on the finger) with RA. Enthesitis (inflammation of the tendons and ligaments) is also more common in PsA than RA.

 

Causes and Diagnosis

How do doctors make the determination of what type of arthritis you have? When you go in for your first visit, your doctor will take your medical history, perform a physical exam, and also collect some bloodwork. Other diagnostic tests, such as x-rays and MRIs, may also be ordered.

Most people who have PsA have a family history of psoriasis, PsA, or both. Your risk factors for developing PsA are your family history, your age (PsA mostly starts in individuals between 30 and 50), and whether you have psoriasis. In some cases, some type of physical trauma (such as a bacterial or viral infection – like strep throat), can jumpstart the onset of PsA in individuals already predisposed to the disease.

Risk factors for RA include being female, being over the age of 40, smoking, having a family history of RA, and exposure to environmental toxins, such as asbestos and silica. As mentioned above, presence of the Rheumatoid Factor (RF) antigen can confirm a diagnosis of RA.

 

Treatment Options

While both RA and PsA can be very painful and debilitating diseases, treatment options are advanced and result in great pain relief. The key is to catch the symptoms early and stay on top of your treatments.

The most common form of treatment for both PsA and RA are a combination of prescription and over-the-counter medications. Disease-modifying anti-rheumatic drugs (DMARDs) and non-steroidal anti-inflammatory drugs (NSAIDs) are usually prescribed for treatment of both types of arthritis. NSAIDs relieve pain and reduce inflammation. DMARDs slow the progression of joint disease.

Other common medications used in the treatment of both PsA and RA are immunosuppressants, TNF-alpha inhibitors, steroid injections into inflamed joints, and joint replacement surgery (in extreme cases).

Consistent exercise that does not place much stress on the joints, maintaining a healthy weight, and making healthy lifestyle decisions (like quitting smoking) often can also help minimize joint stiffness, joint pain, and fatigue that often accompany both types of arthritis as well.