Can sarcoidosis cause small joint arthritis?

Sarcoidosis and Small Joint Arthritis

Yes, sarcoidosis can cause small joint arthritis, though it more commonly affects larger joints like ankles. Sarcoidosis is a multisystem granulomatous disorder that can present with various musculoskeletal manifestations, including both acute and chronic forms of arthritis.

Types of Articular Involvement in Sarcoidosis

Acute Sarcoid Arthritis

• Most common form of joint involvement in sarcoidosis
• Often presents as part of Löfgren's syndrome (defined as bilateral hilar adenopathy with erythema nodosum and/or periarticular arthritis) 1
• Typically self-limiting and resolves without permanent joint damage 2
• Predominantly affects ankles and other large joints 3

Chronic Sarcoid Arthritis

• Less common but more likely to involve small joints
• Can progress to cause joint deformities 2
• More likely to involve upper limb joints, including:
  • Shoulders
  • Wrists
  • Metacarpophalangeal (MCP) joints
  • Proximal interphalangeal (PIP) joints 3
• Often associated with other systemic manifestations of sarcoidosis

Clinical Presentation and Diagnosis

When evaluating for small joint involvement in sarcoidosis, look for:

• Inflammatory arthritis affecting MCP and PIP joints 3
• Periarticular soft tissue swelling
• Tenosynovitis and dactylitis 2
• Associated systemic features such as:
  • Bilateral hilar lymphadenopathy
  • Pulmonary infiltrates
  • Skin lesions (erythema nodosum, lupus pernio)
  • Ocular involvement (uveitis, scleritis) 4

Diagnosis requires:

1. Compatible clinical and radiologic presentation
2. Pathologic evidence of non-caseating granulomas
3. Exclusion of other diseases with similar findings 4

Differential Diagnosis

Small joint arthritis in sarcoidosis must be distinguished from:

• Rheumatoid arthritis
• Psoriatic arthritis
• Gout
• Other inflammatory arthritides 1

Treatment Approaches

Treatment of sarcoid arthritis depends on the type and severity:

1. Acute sarcoid arthritis:

   • NSAIDs are first-line therapy 5
   • Usually self-limiting with good prognosis 3

2. Chronic sarcoid arthritis affecting small joints:

   • Corticosteroids for persistent symptoms 5
   • For steroid-sparing options:
     • Hydroxychloroquine 1, 3
     • Methotrexate 3, 5
     • TNF-alpha antagonists (e.g., infliximab) for refractory cases 1, 6

Prognosis and Monitoring

• Acute arthritis typically resolves completely (40 out of 49 patients achieved complete remission in one study) 3
• Chronic arthritis may require long-term immunosuppressive therapy but can achieve remission (12 out of 16 patients in one study) 3
• Regular monitoring for disease progression and treatment response is essential

Key Points to Remember

• While sarcoidosis most commonly affects ankles and larger joints, small joint involvement does occur, particularly in chronic sarcoid arthritis
• Small joint involvement is more common in chronic than acute sarcoid arthritis
• Chronic sarcoid arthritis is more frequently associated with other extrapulmonary manifestations, particularly peripheral lymphadenopathy and uveitis 3
• The presence of small joint arthritis may indicate a more persistent form of sarcoidosis requiring more aggressive treatment

When evaluating a patient with small joint arthritis of unknown etiology, consider sarcoidosis in the differential diagnosis, especially if there are other suggestive systemic features.