Rheumatoid Arthritis vs. Psoriatic Arthritis

• Rheumatoid arthritis: A type of chronic inflammatory condition in which the body’s immune system attacks its joints (causing their inflammation or arthritis) and other tissues and organs.
• Psoriatic arthritis: A type of chronic inflammatory condition that causes damage to the joints. It occurs in about 30 percent of people with psoriasis (a type of skin condition).

Rheumatoid arthritis (RA)

Signs and symptoms of RA may not stay the same all the time. There may be periods of worsening symptoms called flare-ups or improvements in symptoms called remission. 

Symptoms and signs of RA are divided into two main categories:

1. Articular manifestations: These refer to the signs and symptoms related to the joints. Joint involvement is the hallmark of RA. It initially affects the small joints (such as those of the fingers and toes), but later, it may progress to involve larger joints (such as the knees, shoulders, elbows, and hips).
   • Articular signs and symptoms may include:
     • Joint pain involving one or more joints
     • Joint swelling involving one or more joints
     • Symmetric arthritis (joints on both sides, right and left, of the body affected)
     • Joint stiffness particularly in the morning or after periods of rest or inactivity
2. Extra-articular manifestations: These refer to the signs and symptoms that do not involve the joints.
   • Extra-articular signs and symptoms are seen in about 40 percent of people with RA and include:
     • Fever
     • Fatigue
     • Weight loss
     • Appetite loss
     • Weakness
     • Anemia
     • Dry eyes
     • Dry mouth
     • Involvement of other organs such as:
       • Skin
       • Heart
       • Lungs
       • Kidneys

Psoriatic arthritis

Symptoms of psoriasis may vary in severity. Some people may develop psoriatic arthritis before the development of skin psoriasis. The severity of psoriatic arthritis is not correlated with that of skin psoriasis.

Typical symptoms of psoriatic arthritis include:

• Painful and tender joints
• Asymmetric arthritis (unlike RA, although some may have symmetric arthritis)
• Swollen joints
• Joint stiffness particularly in the morning
• Fatigue
• Reduced range of motion
• Nail changes (such as pitted nails or separation of nails from the nail bed)
• Sausage-like swollen toes and fingers
• Eye pain or redness
• Blurred vision
• Low backache
• Skin rash (such as red flaky skin lesions with silvery scales)
• Pitting of nails
• Urogenital involvement (such as inflammation of the vagina, cervix, urethra, penis, or prostate gland)
• Involvement of other organs such as:
  • Heart
  • Gut
  • Liver

Untreated psoriasis can lead to severe joint involvement, causing permanent joint deformity (arthritis mutilans). Psoriatic arthritis can increase the risk of other diseases such as heart diseases, high blood pressure, and diabetes.

Rheumatoid arthritis (RA)

The exact cause of RA is unknown. The disease occurs due to autoimmune attacks on the joints and other tissues.

Some of the factors that can increase your likelihood of getting RA include:

• Female gender (women have a two to three times higher risk of RA than men)
• Older age (greatest risk in people in their 60s)
• Smoking
• Genetic factors
• Being overweight or obese
• Parity (women who have never given birth are at an increased risk of RA)

Studies report that children born to lower-income families or those exposed to cigarette smoke in early life have a higher risk of RA than adults.

The only protective factor against RA in women is breastfeeding. Women who breastfeed their babies have reduced RA risk compared with those who don’t.

Psoriatic arthritis

The exact cause of psoriatic arthritis is unknown. Psoriatic arthritis develops in people with psoriasis in which the immune system attacks the joints and surrounding tissues besides the skin cells (called keratinocytes).

Several genes, such as the HLA gene, may play a role in causing this condition. About 40 percent of people with psoriatic arthritis may have a family history of psoriasis or psoriatic arthritis. How this disease is inherited is yet not well understood. Certain viral or bacterial infections may trigger psoriatic arthritis in genetically susceptible individuals.

Some of the risk factors for psoriatic arthritis include:

• Having psoriasis
• Having a family history of psoriasis or psoriatic arthritis
• Being 30 to 55 years of age
• Certain bacterial (such as Strep) or viral (such as human immunodeficiency virus) infections
• Following a joint injury in a person with psoriasis
• Being overweight or obese
• Smoking

Rheumatoid arthritis (RA)

RA is diagnosed based on detailed medical history, physical examination, and certain tests such as:

• Blood tests: These include tests for autoantibodies in the blood (such as rheumatoid factor and anti-cyclic citrullinated peptide antibody). Other blood tests may be performed to look for inflammation (such as erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]), liver involvement (liver function tests), and kidney involvement (kidney function tests).
• Imaging studies: These include X-ray, computed tomography (CT) scan, and magnetic resonance imaging (MRI).
• Other tests: Echocardiography may be done to look for heart involvement. Pulmonary function tests may be done to assess lung involvement.

Psoriatic arthritis

Doctors may diagnose psoriatic arthritis based on detailed medical history and physical examination including nail and skin examination for psoriasis.

They may order certain tests such as:

• Blood tests: They help exclude RA and other causes of arthritis. There may be increased levels of ESR and CRP.
• Imaging studies: These include X-ray, CT scan, and MRI.
• Synovial fluid examination: This involves collecting joint fluid through a needle and examining the fluid under a microscope.

Rheumatoid arthritis (RA)

RA is a chronic disease with no specific cure. Proper treatment can control the symptoms, allowing remission and preventing further damage. Medications that primarily relieve RA symptoms and prevent or slow down further damage are called disease-modifying anti-rheumatic drugs (DMARDs).

RA treatment generally includes:

• Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen
• Corticosteroids such as prednisone
• DMARDs such as sulfasalazine, methotrexate and leflunomide
• Biological response modifiers or biologicals such as abatacept, adalimumab, and tocilizumab
• Janus kinase (JAK) inhibitors such as baricitinib, tofacitinib, and upadacitinib
• Physical therapy
• Surgery may include soft tissue (such as a tendon) repair, removal of the inflamed joint lining (synovectomy), joint fusion (arthrodesis), or joint replacement surgery

Psoriatic arthritis

Like RA, psoriatic arthritis cannot be cured. Treatment, however, can help limit the progression of the disease, provide symptomatic relief and prevent complications.

• NSAIDs such as ibuprofen and naproxen
• DMARDs such as sulfasalazine, methotrexate, and leflunomide
• Biological response modifiers or biologicals such as adalimumab, certolizumab, and etanercept
• JAK inhibitors such as tofacitinib
• Phosphodiesterase-4 inhibitors such as apremilast
• Physical therapy
• Intraarticular (injected into the joint) steroids
• Surgery such as total joint replacement