Psoriasis Australia

Distal Interphalangeal Predominant (DIP PsA)

Distal interphalangeal predominant psoriatic arthritis (DIP PsA) is a subtype of psoriatic arthritis that primarily affects the small joints at the ends of the fingers and toes, known as the distal interphalangeal (DIP) joints.

Overview

Distal interphalangeal predominant psoriatic arthritis (DIP PsA) is a subtype of psoriatic arthritis that primarily affects the small joints at the ends of the fingers and toes, known as the distal interphalangeal (DIP) joints. This form of arthritis is commonly associated with nail changes such as pitting, onycholysis (separation of the nail from the nail bed), and discoloration, which are hallmark features of psoriatic nail disease.

Symptoms of DIP PsA

  • Pain and Swelling: Inflammation of the DIP joints causes pain, tenderness, and visible swelling, which can affect grip strength and dexterity.
  • Nail Changes: Up to 80% of patients with DIP PsA experience nail changes, including pitting, ridging, and crumbling of the nails.
  • Stiffness: Joint stiffness is commonly worse in the morning and can last for hours, depending on the severity of inflammation.
  • Limited Range of Motion: Chronic inflammation may lead to decreased flexibility in the fingers or toes, making daily activities challenging.
  • Dactylitis: In some cases, the entire finger or toe may become swollen, a condition called “dactylitis” or “sausage digits.”

Diagnosis

Diagnosing DIP PsA involves a combination of clinical evaluation, imaging studies, and laboratory tests. Rheumatologists will assess joint swelling and nail involvement, often using X-rays, ultrasound, or MRI to evaluate joint damage. Blood tests are also performed to rule out other forms of arthritis such as rheumatoid arthritis, but DIP PsA typically does not involve high levels of rheumatoid factor or anti-cyclic citrullinated peptide antibodies (anti-CCP), which are characteristic of rheumatoid arthritis.

Treatment Options

DIP PsA is a chronic condition that requires long-term management. Treatment focuses on reducing inflammation, controlling symptoms, and preventing joint damage.

Topical Treatments:

    • Corticosteroids: These are often used to manage localized inflammation in both the skin and joints.
    • Topical NSAIDs: Nonsteroidal anti-inflammatory drugs (NSAIDs) may be applied to affected areas to alleviate pain and swelling.

Systemic Medications:

    • Non-Biologic Disease-Modifying Antirheumatic Drugs (DMARDs): Methotrexate and sulfasalazine are commonly prescribed in Australia for managing joint inflammation and preventing progression of joint damage. These medications suppress the immune system to reduce overall inflammation.
    • Biologic DMARDs: Biologic medications such as TNF inhibitors (e.g., adalimumab, etanercept) or IL-17 inhibitors (e.g., secukinumab, ixekizumab) target specific pathways in the immune system and are highly effective in controlling joint symptoms and skin disease. These are available through the Pharmaceutical Benefits Scheme (PBS) in Australia.
    • Janus Kinase (JAK) Inhibitors: These oral medications, such as tofacitinib, target specific enzymes that contribute to inflammation. They may be used when other treatments are not effective or appropriate.

Physical Therapy:

    • Occupational Therapy: Hand therapy and exercises prescribed by occupational therapists may improve hand function and reduce stiffness in the DIP joints.
    • Splinting: Using finger or toe splints can stabilize joints during flare-ups, helping reduce discomfort and protect against further damage.

Lifestyle Modifications:

    • Weight Management: Maintaining a healthy weight can reduce the load on affected joints, slowing disease progression.
    • Smoking Cessation: Smoking is a known risk factor for developing PsA and worsening symptoms. Quitting smoking may help improve treatment outcomes.

Living with DIP PsA

People living with DIP PsA often need to adapt their daily routines to manage symptoms. Regular exercise, healthy eating, and stress management are essential components of a comprehensive care plan. Staying active helps maintain joint flexibility and prevents muscle atrophy, but it is important to avoid activities that strain the joints.

Support groups, both in-person and online, can provide emotional support and practical advice for managing daily challenges. Connecting with others who have similar experiences can offer valuable insights into living with psoriatic arthritis.

Summary

DIP PsA is a challenging but manageable condition. With appropriate treatment and support, many people living with this form of psoriatic arthritis lead full, active lives. Early diagnosis and consistent treatment are essential in preventing joint damage and improving quality of life.