What is the Difference Between Ankylosing Spondylitis and Psoriatic Arthritis?

Ankylosing spondylitis (AS) and psoriatic arthritis (PsA) are both forms of arthritis that cause joint swelling, stiffness, and pain. However, there are key differences between the two conditions:

Affected areas: AS primarily affects the spine and sacroiliac joints (where the spine connects to the pelvis), although other joints can also be involved. In contrast, PsA primarily affects the hands and feet, as well as large joints like the knees and ankles.
Symptom distribution: While AS is considered "axial" and PsA is considered "peripheral," symptoms can overlap in some cases. However, the main difference lies in the specific joints affected in each condition.
Associated conditions: AS is a type of spondyloarthritis that mainly affects the spine and lower back. PsA, on the other hand, usually occurs in people with psoriasis, an autoimmune condition that causes skin cells to develop rapidly, leading to various skin symptoms.
Radiographic features: Axial psoriatic arthritis develops at an older age, is less symptomatic, and is associated with distinct radiographic features compared to AS.

Both AS and PsA can cause permanent damage to joints if left untreated. Although they share some similarities, there are distinct differences in the affected areas, symptom distribution, and associated conditions. These differences help in diagnosing and managing the appropriate condition.

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What is the Difference Between Ankylosing Spondylitis and Psoriatic Arthritis?

Comparative Table: Ankylosing Spondylitis vs Psoriatic Arthritis

Ankylosing spondylitis (AS) and psoriatic arthritis (PsA) are both types of spondyloarthritis that cause joint swelling, stiffness, and pain. They share some similarities but also have distinct differences. Here is a table comparing the key differences between ankylosing spondylitis and psoriatic arthritis:

Feature	Ankylosing Spondylitis (AS)	Psoriatic Arthritis (PsA)
Primary Affected Joints	Spine and sacroiliac joints (where the spine connects with the pelvis)	Hands, feet, knees, and sometimes back
Type of Arthritis	Axial (primarily affecting the spine)	Peripheral (affecting other joints like hands, knees, and feet)
Association with other Conditions	Mainly affects the spine, but can also affect other joints	Usually occurs in people with psoriasis, an autoimmune condition causing skin symptoms
Sacroiliitis	Hallmark of the disease	Less frequent feature
Spondylitis	Usually occurs after sacroiliitis	Can occur without sacroiliitis in 35% of cases
Severity of Joint Damage	More severe, with syndesmophytes forming bridges and causing complete ankylosis	Less severe, with less complete ankylosis and non-bridging syndesmophytes

Both conditions can be challenging to diagnose and are considered incurable. However, various therapies and treatment options are available to help manage symptoms and improve the quality of life for patients.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.