What is the appropriate management for a patient with polyarthritis and sore feet, potentially indicating inflammatory arthritis?

Management of Polyarthritis with Sore Feet

For a patient presenting with polyarthritis and sore feet suggesting inflammatory arthritis, initiate a conventional synthetic DMARD (csDMARD) rapidly—preferably methotrexate—within 2 weeks of diagnosis, while using NSAIDs for symptomatic relief during the initial assessment period. 1

Initial Clinical Assessment

Confirm inflammatory arthritis by identifying key features that distinguish it from non-inflammatory conditions:

• Morning stiffness lasting >30 minutes (often 2+ hours in inflammatory disease) 1, 2
• Palpable joint swelling or effusion with warmth and tenderness, particularly in the small joints of hands and feet 1
• Foot involvement patterns: forefoot most commonly affected (90% of inflammatory arthritis patients report foot pain), with metatarsophalangeal joints, midfoot, and ankle involvement 3, 4
• Systemic symptoms: fatigue, weight loss, or fever suggest inflammatory etiology 2

Obtain baseline laboratory studies: rheumatoid factor, anti-CCP antibodies, ESR/CRP, complete blood count, and metabolic panel 1, 4

Perform plain radiographs of hands and feet to assess for erosive changes, though early disease may show normal films 1, 5

First-Line Pharmacological Management

Immediate Symptomatic Relief

NSAIDs may be used to relieve musculoskeletal signs and symptoms while awaiting definitive diagnosis 1

• Consider cardiovascular and gastrointestinal risks before prescribing 6, 7
• NSAIDs provide no disease-modifying effect and do not prevent joint damage 6

Local glucocorticoid injections should be considered as adjunctive therapy for severely affected joints 1

• Systemic glucocorticoids may be used cautiously at the lowest effective dose for short periods only 1
• Avoid systemic steroids for chronic use due to risk of psoriasis flare if psoriatic arthritis is in the differential 1

Disease-Modifying Therapy

In patients with polyarthritis (≥5 swollen joints), initiate a csDMARD rapidly—delays should not exceed 2 weeks 1

Methotrexate is the preferred first-line csDMARD, particularly when skin involvement suggests psoriatic arthritis 1, 6, 8

• Start at appropriate dosing per FDA labeling for rheumatoid arthritis management 8
• Alternative csDMARDs include sulfasalazine or leflunomide if methotrexate is contraindicated 1
• Continue NSAIDs, low-dose steroids, and physiotherapy as needed during DMARD initiation 8

Treatment Target and Monitoring

Aim for remission or, alternatively, low disease activity through regular assessment and therapy adjustment 1, 6

Evaluate treatment response at 3-6 months after initiating csDMARD therapy 1

• If insufficient response, advance to biologic DMARD (bDMARD) therapy 1
• Assessment should include joint counts, patient global assessment, physical function (HAQ), acute phase reactants, and radiographic progression 1

Escalation to Biologic Therapy

With inadequate response to at least one csDMARD, commence therapy with a bDMARD 1, 6

For peripheral arthritis with relevant skin involvement, prefer IL-17 inhibitor or IL-12/23 inhibitor over TNF inhibitors 1, 6

For predominantly axial disease or enthesitis unresponsive to NSAIDs, consider TNF inhibitor (or IL-17 inhibitor if skin involvement present) 1

Special Considerations for Foot Involvement

Enthesitis (inflammation at tendon/ligament insertion sites) commonly affects:

• Plantar fascia insertion 1
• Achilles tendon insertion 1
• Ligamentous attachments to midfoot 1

Dactylitis ("sausage digit") represents combined enthesitis and synovitis requiring systemic therapy, not just local measures 1

For unequivocal enthesitis with insufficient response to NSAIDs or local glucocorticoid injections, therapy with a bDMARD should be considered 1

Critical Pitfalls to Avoid

• Do not delay DMARD initiation beyond 2 weeks in confirmed polyarthritis—early intervention prevents irreversible joint damage and disability 1
• Do not rely on NSAIDs alone for chronic management—they provide no disease modification 6
• Do not use systemic corticosteroids chronically—reserve for short-term bridging therapy only 1
• Do not assume normal radiographs exclude inflammatory arthritis—erosive changes may not appear until later in disease course 1, 5
• Do not overlook extra-articular manifestations (skin, eyes, GI tract) or comorbidities (metabolic syndrome, cardiovascular disease) that influence treatment selection 1

Differential Diagnosis Considerations

While managing as inflammatory polyarthritis, maintain awareness of alternative diagnoses:

• Psoriatic arthritis: nail changes, dactylitis, enthesitis, skin involvement 1
• Rheumatoid arthritis: symmetric small joint involvement, positive RF/anti-CCP 4, 2
• Seronegative spondylarthropathies: asymmetric oligoarthritis, axial involvement 9, 5
• Crystal arthropathies or viral arthritis: acute, self-limited presentations 2, 5

Rheumatology consultation is essential when diagnosis is uncertain or when escalation to biologic therapy is needed 1