Psoriatic arthritis (PsA) is a chronic autoimmune condition that causes inflammation in the joints of people who also have psoriasis—a skin disease marked by red, scaly patches. Around 20–30% of people with psoriasis develop PsA, most often between the ages of 30 and 50.

Because PsA and rheumatoid arthritis (RA) share similar symptoms such as joint pain and swelling, the two are sometimes mistaken for one another. However, PsA has unique characteristics, including nail and skin changes, and may affect different joints or areas of the body.

There are five main types of psoriatic arthritis, each defined by the specific joints involved and the severity of inflammation:

  1. Asymmetric psoriatic arthritis

  2. Symmetric psoriatic arthritis

  3. Distal interphalangeal (DIP) predominant arthritis

  4. Spondylitis

  5. Arthritis mutilans

It’s also possible to experience more than one subtype at the same time, and symptoms can change as the disease progresses.

Asymmetric Psoriatic Arthritis

This is the most common early form of PsA. Asymmetric arthritis affects different joints on opposite sides of the body—for example, one wrist or one knee may hurt while the other side feels normal.

About 60% of people with PsA experience this asymmetric form initially, though it may progress into a more widespread pattern over time.

common symptoms:

  • Stiff or painful joints on one side of the body

  • Redness, swelling, and warmth around affected joints

  • “Sausage digits” (swollen fingers or toes, known as dactylitis)

Symmetric Psoriatic Arthritis

symmetric psoriatic arthritis affects the same joints on both sides of the body, such as both wrists or both knees. This type accounts for 50–60% of PsA cases and often resembles rheumatoid arthritis.

However, PsA differs from RA because it may also involve the small joints near the fingertips (distal interphalangeal joints).

common symptoms:

  • Stiffness and pain in matching joints on both sides

  • Swelling and tenderness in multiple joints

  • Dactylitis and reduced flexibility

This form tends to be more chronic and may cause long-term joint damage if not treated early.

Distal Interphalangeal (DIP) Predominant

This subtype mainly affects the joints closest to the nails—the ends of the fingers and toes. It represents around 20% of PsA cases and is strongly associated with nail psoriasis.

common symptoms:

  • Nail pitting, ridging, or separation from the nail bed

  • Crumbling or discoloration of nails

  • Swelling and stiffness in fingers or toes

  • Dactylitis in affected digits

DIP-predominant PsA can be mild at first but may progress to more extensive joint involvement without treatment.

Spondylitis

spondylitic psoriatic arthritis affects the spine and sacroiliac joints (where the spine connects to the pelvis). This form occurs in 7–32% of people with PsA and can cause stiffness, back pain, and reduced flexibility.

common symptoms:

  • Pain and stiffness in the lower back or neck

  • Limited mobility of the spine

  • Pain radiating to arms, hips, or legs

  • Morning stiffness that improves with movement

This type overlaps with ankylosing spondylitis, another inflammatory spinal disease, and may also involve peripheral joints like the hips or knees.

Arthritis Mutilans

arthritis mutilans is the rarest yet most severe form of psoriatic arthritis, occurring in fewer than 5% of patients. It causes severe joint destruction and bone loss, leading to deformity—most often in the hands and feet.

common symptoms:

  • Intense inflammation and swelling in small joints

  • Bone erosion (osteolysis) visible on imaging scans

  • Shortened or “telescoping” fingers and toes

  • Chronic pain in the neck, back, or other joints

Because arthritis mutilans progresses rapidly, early detection and aggressive treatment are essential to prevent permanent disability.

Diagnosis

Diagnosing PsA can be challenging since no single test confirms it, and symptoms vary greatly between individuals. There’s often no correlation between the severity of psoriasis and joint symptoms.

diagnostic steps may include:

  • Medical and family history: Up to half of PsA patients have a close relative with psoriasis or PsA.

  • Blood tests: Checking inflammation markers like CRP and ESR, while ruling out rheumatoid factor (which is usually negative in PsA).

  • Imaging tests: X-rays or MRI scans to detect joint erosion or spinal inflammation.

  • Bone density scans: To evaluate potential bone loss.

Testing also helps rule out conditions such as rheumatoid arthritis and gout, which can mimic PsA symptoms.

Treatment

Treatment for PsA focuses on reducing inflammation, protecting joints, and improving quality of life, regardless of subtype.

medication options include:

  • NSAIDs (e.g., ibuprofen, naproxen): Relieve pain and swelling with consistent use.

  • Corticosteroid injections: Provide short-term inflammation relief in specific joints.

  • DMARDs (Disease-Modifying Antirheumatic Drugs): Such as methotrexate, leflunomide (Arava), or sulfasalazine (Azulfidine), which slow disease progression.

  • Targeted oral medications: Like Otezla (apremilast), RINVOQ (upadacitinib), and Xeljanz (tofacitinib) to regulate immune response.

biologic treatments:
These medications target specific immune pathways that cause inflammation. They are usually delivered as injections or IV infusions.

  • TNF inhibitors: Such as etanercept (Enbrel), adalimumab (Humira), and infliximab (Remicade).

  • Interleukin inhibitors: Block inflammatory proteins like IL-17, IL-23, or IL-12. Examples include Cosentyx (secukinumab), Stelara (ustekinumab), and Tremfya (guselkumab).

supportive treatments:

  • Physical therapy and gentle exercise to maintain joint mobility

  • Heat or cold therapy for stiffness and pain relief

  • Stress management and balanced diet to reduce inflammation

A Quick Review

There are five main types of psoriatic arthritis—asymmetric, symmetric, distal interphalangeal, spondylitic, and mutilans—each with unique patterns and levels of severity.

While no test can definitively diagnose PsA, early treatment can help prevent joint damage and long-term complications.
Most people manage PsA successfully through medication, lifestyle changes, and consistent medical care.