What type of arthritis is characterized by changes in the distal and proximal interphalangeal (PIP) joints?

From the Guidelines

Psoriatic arthritis (PsA) is the type of arthritis most commonly characterized by changes in the distal and proximal interphalangeal (PIP) joints, particularly when accompanied by nail changes, as noted in the 2019 American College of Rheumatology/National Psoriasis Foundation guideline for the treatment of PsA 1.

Key Characteristics of PsA

• PsA is a chronic inflammatory musculoskeletal disease associated with psoriasis, manifesting most commonly with peripheral arthritis, dactylitis, enthesitis, and spondylitis.
• The incidence of PsA is ~6 per 100,000 per year, and the prevalence is ~1–2 per 1,000 in the general population.
• PsA affects men and women equally, with the distribution of peripheral arthritis varying from asymmetric oligoarthritis to symmetric polyarthritis.

Differentiation from Other Types of Arthritis

• Osteoarthritis commonly affects the DIP joints, causing Heberden's nodes and Bouchard's nodes, which are hallmarks of osteoarthritis in the hands.
• Rheumatoid arthritis typically spares the DIP joints while prominently affecting the PIP joints, often in a symmetrical pattern across both hands.
• Gouty arthritis may affect individual DIP or PIP joints during acute attacks, causing intense pain, redness, and swelling.

Clinical Features and Treatment

• PsA is associated with an adverse impact on health-related quality of life and high health care costs and utilization.
• Early identification of PsA and early initiation of therapy are important for improving long-term outcomes, as noted in the guidelines for the management of psoriasis and psoriatic arthritis 1.
• Treatment options for PsA include nonpharmacologic and pharmacologic therapies, such as nonsteroidal anti-inflammatory drugs (NSAIDs), intraarticular injections, and immunomodulatory therapies.

From the Research

Arthritis Characterized by Changes in Distal and Proximal Interphalangeal (PIP) Joints

• The type of arthritis characterized by changes in the distal and proximal interphalangeal (PIP) joints is Psoriatic Arthritis (PsA) 2.
• PsA is more likely to suggest involvement of the DIP joints and proliferative bone changes, whereas lesions affecting the PIP joints, wrist, or styloid process of the radius are more common in patients with seropositive Rheumatoid Arthritis (RA) than in those with PsA 2.
• Rheumatoid Arthritis (RA) can also affect the PIP joints, and it is usually found in metacarpophalangeal, proximal interphalangeal and metatarsophalangeal joints, as well as in the wrists and knee 3.
• The clinical features of RA vary, but an insidious onset of pain with symmetric swelling of small joints is the most frequent finding, and morning stiffness in and around the joints is a typical sign of RA 3.
• The prevalence of joint space narrowing and/or erosions in each proximal interphalangeal (PIP) joints ranged between 11% and 18% in patients with classical Rheumatoid Arthritis 4.

Key Findings

• Lesions in PIP, MCP, and wrist joints, as well as erosions, advanced bone damage, joint subluxations, dislocations, and joint space narrowing, were more common in seropositive RA patients than in seronegative RA patients 2.
• DIP joint involvement was generally unilateral and asymmetric, with the 3rd finger being the most commonly affected joint in patients with RA 5.
• Older age was an independent predictive factor for DIP erosion in patients with RA 5.
• The wrist was the most common joint involved both by physical examination (67%) and radiographically (70%) in patients with long standing RA 4.