What could cause my swollen, purple, painful fingers persisting for two months and how should I be evaluated and treated?

Swollen, Purple, Painful Fingers for Two Months: Evaluation and Management

You need urgent rheumatology evaluation for suspected psoriatic arthritis with dactylitis, which can cause permanent joint damage if treatment is delayed beyond 2 years. 1

Most Likely Diagnosis: Psoriatic Arthritis with Dactylitis

The two-month duration of swollen, purple, painful fingers strongly suggests psoriatic arthritis (PsA) with dactylitis ("sausage digits"), particularly if multiple fingers are involved. 2, 1 This presentation is characteristic and affects 16-48% of PsA patients. 1

Critical Features to Assess Immediately

Examine for these diagnostic clues:

• Nail changes: Look for pitting, onycholysis (nail separation), or severe nail dystrophy—these strongly correlate with PsA and are present in the majority of patients with finger joint involvement. 2, 1
• Skin lesions: Check scalp, elbows, knees, genitals, and the fingers themselves for psoriatic plaques (rough, scaly patches). 2, 1
• Morning stiffness: Duration >30 minutes is diagnostically valuable. 1
• Joint pattern: PsA commonly affects distal finger joints (near the nails) and knuckles, often asymmetrically. 2, 1

Why This Matters for Morbidity and Mortality

Delayed treatment leads to irreversible joint destruction. Radiographic damage occurs in 7-47% of patients within just 2 years despite standard therapy, causing severe physical limitations and permanent disability. 1 The vast majority of PsA patients have skin disease for up to 12 years before joint symptoms appear, making early recognition critical. 2, 1

Urgent Diagnostic Workup

Order these tests now:

• Rheumatoid factor (should be negative in PsA) 2
• C-reactive protein and ESR to measure systemic inflammation 1
• Complete metabolic panel and CBC 3
• X-rays of affected fingers to assess for early joint damage 1

Refer to rheumatology immediately—do not wait for test results if clinical suspicion is high. 1 Rheumatologists will perform comprehensive joint assessment including tender and swollen joint counts. 1

Alternative Diagnoses to Rule Out

Vascular Steal Syndrome (If Patient Has Dialysis Access)

This is a surgical emergency if present. If the patient has an arteriovenous fistula for dialysis, purple painful fingers represent Stage II-III steal syndrome and can progress rapidly to gangrene requiring amputation. 2, 3

Key distinguishing features:

• Occurs in dialysis patients with arm AV fistula 2
• Fingers are cold (not warm) 2
• Pain worsens during dialysis 2
• Can progress from slow deterioration to rapid necrosis within weeks 2, 3

If suspected: Immediate vascular surgery referral—do not delay. Perform digital blood pressure measurement and duplex Doppler ultrasound. 2, 3 Threatened limb viability requires urgent fistula ligation. 2, 3

Dermatomyositis (If Weakness Present)

Check for proximal muscle weakness (shoulders, hips—not hand muscles). 3 If present with purple skin changes:

• Look for Gottron papules over knuckles and heliotrope rash around eyes 3
• Order urgent CK, aldolase, AST, ALT, LDH (CK can be >10× normal) 3
• Obtain myositis-specific autoantibody panel 3
• This requires aggressive immunotherapy and cancer screening 3

Achenbach's Syndrome (Benign Paroxysmal Finger Hematoma)

This is a diagnosis of exclusion presenting with sudden painful purple/blue bruising of fingers, predominantly on the palm side but sparing the fingertips. 4, 5 It affects primarily women, is completely benign, and resolves spontaneously in 4-7 days. 4, 5 However, the two-month duration in your case makes this unlikely—Achenbach's episodes are acute and self-limited. 4, 5

Raynaud's Phenomenon with Secondary Connective Tissue Disease

If fingers turn white→blue→red with cold exposure or stress, consider secondary Raynaud's associated with scleroderma (90-95% have Raynaud's), lupus, or mixed connective tissue disease. 6 Order ANA, anticentromere antibodies, and anti-U1-RNP. 6 Perform nailfold capillaroscopy looking for enlarged capillaries, hemorrhages, and avascular areas. 6

Treatment Algorithm for Psoriatic Arthritis

Once PsA is confirmed:

Mild Disease (Few Joints, Minimal Impact)

• Start NSAIDs alone 1
• If unresponsive after 2-3 months, escalate to methotrexate 1

Moderate to Severe Disease (Multiple Joints, Dactylitis, Functional Impairment)

• First-line: Methotrexate 25 mg weekly + folic acid 1 mg daily 2, 1
• If inadequate response after 12 weeks, add TNF-alpha inhibitor (etanercept, adalimumab, or infliximab) 2, 1
• Alternative: Combination oral cyclosporine with methotrexate 1
• For dactylitis specifically, systemic therapy is required—topical treatment is insufficient 1

The combination of methotrexate plus TNF-alpha blocker can produce dramatic improvement within 4 months and significantly improve quality of life. 2

Critical Pitfalls to Avoid

• Do not dismiss purple swelling as "just bruising"—two months is far too long for benign conditions like Achenbach's syndrome. 4, 5
• Do not delay rheumatology referral waiting for "more symptoms"—joint damage begins early and is irreversible. 1
• Do not assume skin and joint severity correlate—patients can have severe PsA with minimal skin disease. 1
• In dialysis patients, do not attribute symptoms to "poor circulation"—steal syndrome requires immediate surgical intervention. 2, 3
• Check for nail changes carefully—they are easily overlooked but strongly predict PsA. 2, 1