The 5 Types of Psoriatic Arthritis—And the Common Symptoms Associated With Each

The different subtypes depend on which parts of the body are affected, and the severity of disease.

Chronic illnesses are incredibly diverse and dynamic, often presenting a unique and complex set of challenges for individuals who bear their burden. One striking example of this intricate landscape is Psoriatic Arthritis (PsA), an autoimmune disease characterized by inflammation in the joints that frequently coexists with the skin condition psoriasis. While PsA appears straightforward at first glance, it is actually a multifaceted condition, with five distinct subcategories, each distinguished by the specific joints it affects: symmetric psoriatic arthritis, asymmetric psoriatic arthritis, distal psoriatic arthritis, spondylitis, and arthritis mutilans.

Before delving into the intricacies of these PsA subcategories, it is essential to clarify that, in the broader context of treatment options, the specific type of PsA one has does not typically lead to vastly different care strategies. Magdalena Perez-Rivera, MD, a rheumatology specialist at Conviva Care Centers, emphasizes that “We treat them all the same.” In fact, she cautions that delving too deeply into these subcategories might even “overcomplicate” matters for patients and their caregivers.

However, distinguishing between the types of PsA can be invaluable for several reasons. It aids in monitoring symptoms more effectively and provides crucial details about an individual’s diagnosis. It is also noteworthy that some individuals may experience multiple types of PsA or witness a transformation in their specific subtype as the disease progresses. In the following sections, we will explore the different subtypes of Psoriatic Arthritis and the unique symptoms associated with each.

1. Symmetric Polyarthritis

Symmetric polyarthritis, also known as symmetric PsA, is characterized by joint inflammation that affects both sides of the body concurrently. In simpler terms, if you have symmetric PsA, both knees, for instance, would be afflicted, rather than just one. This subtype stands as the most common form, accounting for approximately half of all PsA cases. It bears a resemblance to rheumatoid arthritis (RA) in its presentation.

Symptoms associated with symmetric polyarthritis can vary in intensity, ranging from mild to severe. These symptoms may include:

• Stiff and painful joints that mirror each other on both sides of the body.
  
• Redness, heat, and swelling in the surrounding tissue of the affected joints.
  
• The emergence of a “sausage-like” appearance in fingers or toes due to inflammation, particularly when the hands or feet are affected.
  
• General PsA symptoms, such as patches of red, irritated skin covered in scales, changes in fingernails or toenails, or stiffness and pain that intensifies in the morning.

It is crucial to recognize that symmetric polyarthritis can affect any joint in the body, as highlighted by the US National Library of Medicine (NLM).

2. Asymmetric Oligoarticular

Asymmetric oligoarticular, more commonly referred to as asymmetric PsA, differentiates itself by causing symptoms in different joints on each side of the body. In essence, if you have this subtype, you may experience symptoms in one wrist but not the other, or you might encounter pain and stiffness on one side of the body more frequently than the other.

Common symptoms associated with asymmetric oligoarticular PsA, per the NLM, encompass:

• Stiff and painful joints on different sides of the body.
  
• Redness, heat, and swelling in the tissue surrounding the affected joints.
  
• The development of a “sausage-like” appearance in fingers or toes due to inflammation, especially when the hands or feet are affected.
  
• General PsA symptoms, such as patches of red, irritated skin covered in scales, changes in fingernails or toenails, or stiffness and pain that intensifies in the morning.

3. Distal Interphalangeal Predominant

The distal interphalangeal predominant joints refer to the joints nearest to the nails on fingers and toes. This specific type of PsA primarily targets the ends of fingers and toes. Nail abnormalities are a hallmark of this subtype, including pitting, ridging, crumbling, or separation from the nail beds. Furthermore, distal PsA is often associated with “sausage digits,” a condition characterized by extreme swelling of fingers and toes. Notably, this type of PsA often occurs concurrently with other PsA subtypes rather than existing in isolation.

Common symptoms of distal interphalangeal predominant PsA, as identified by experts, encompass:

• Swelling of the entire fingers and toes, colloquially known as “sausage digits.”
  
• Severe nail abnormalities, including pitting, discoloration, separation from the nail bed, or even fungal infections.
  
• Pain, swelling, and stiffness in fingers and toes.
  
• General PsA symptoms, such as patches of red, irritated skin covered in scales, changes in fingernails or toenails, or stiffness and pain that intensifies in the morning.

4. Spondylitis

Spondylitis PsA entails the inflammation of the spine, particularly the lower back and sacrum—the structure that connects the lumbar vertebrae to the pelvis. Dr. Perez-Rivera explains that this subtype involves inflammation and erosion that gradually erode the joints, potentially leading to their fusion. Such fusion can severely limit the range of motion in the spine.

However, the impact of spondylitis may not be confined solely to the back; it can extend to affect other regions of the body, including the neck, hips, feet, legs, and arms.

Common symptoms associated with spondylitis PsA, as outlined by the NLM, include:

• Pain and stiffness in the back or neck.
  
• Impaired movement in affected areas.
  
• Pain, stiffness, or restricted mobility in joints of the arms, legs, hands, and feet.
  
• General PsA symptoms, such as patches of red, irritated skin covered in scales, changes in fingernails or toenails, or stiffness and pain that intensifies in the morning.

5. Arthritis Mutilans

Arthritis mutilans, the most severe form of PsA, is also the rarest, affecting less than 5% of individuals with PsA, according to the NLM. This subtype, sometimes referred to as psoriatic arthritis mutilans, involves particularly aggressive inflammation and joint damage in the hands and feet. The severity of this inflammation can lead to joint deformation and substantial bone loss.

Symptoms associated with arthritis mutilans, according to the NLM and our experts, encompass:

• Profound inflammation in joints located in the hands and feet.
  
• Deformation of affected joints and associated mobility issues.
  
• Osteolysis, which refers to the loss of bone at the joints.
  
• Telescoping, where the fingers and toes may shorten.
  
• The possibility of neck and back pain in conjunction with arthritis mutilans.
  
• General PsA symptoms, such as patches of red, irritated skin covered in scales, changes in fingernails or toenails, or stiffness and pain that intensifies in the morning.

Understanding these various subtypes of Psoriatic Arthritis provides valuable insights into the complexity of the disease and allows individuals and healthcare providers to tailor their approach to monitoring and managing symptoms. While treatment approaches for PsA typically follow a standardized framework, recognizing the distinct characteristics of each subtype remains essential in optimizing care and enhancing the quality of life for those living with this chronic autoimmune condition.