What type of arthritis causes unilateral swelling on the palm with heat and affects movement at the wrist joint?

Psoriatic Arthritis with Dactylitis

The clinical presentation of unilateral palm swelling with heat affecting wrist movement most strongly suggests psoriatic arthritis (PsA) with dactylitis, particularly given the characteristic combination of inflammatory features and functional impairment. 1

Key Diagnostic Features

Dactylitis ("sausage digit") is a hallmark manifestation of PsA that presents as:

• Inflammation of small joints in the hands with periarticular swelling 1
• Swelling extending along the entire digit into the palm 1
• Associated warmth and erythema indicating active inflammation 1
• Significant functional impairment at adjacent joints including the wrist 1

The unilateral presentation is particularly characteristic of PsA, which commonly presents as asymmetrical oligoarthritis, unlike rheumatoid arthritis which typically shows bilateral symmetry 2, 3

Clinical Presentation Pattern

PsA affecting the hand and wrist demonstrates specific patterns:

• Proximal interphalangeal joints are significantly more frequently affected in PsA compared to RA 4
• Flexor tenosynovitis is significantly more common in PsA than RA (p = 0.022), contributing to palm swelling 5
• Peritendon inflammation of extensor tendons occurs in 13% of metacarpophalangeal joints in PsA versus only 3% in RA 6
• Soft tissue edema extending into the palm is exclusively observed in PsA 6

Distinguishing from Other Arthritides

Rheumatoid Arthritis Differences:

• RA typically presents with bilateral symmetric involvement 2
• RA more frequently affects radiocarpal, midcarpal, and carpometacarpal joints 4
• RA shows more frequent extensor carpi ulnaris tenosynovitis (18.3% vs 2.5% in PsA) 6
• RA demonstrates higher frequency of Power Doppler synovitis (9.2% vs 5% in PsA) 6

Gout Considerations:

While gout can affect the wrist and metacarpophalangeal joints 7, it presents with:

• Acute episodic attacks rather than persistent swelling 7
• Less commonly causes diffuse palm swelling
• Can superimpose on pre-existing osteoarthritis 7

Associated Features to Assess

Cutaneous manifestations are critical for diagnosis:

• Psoriasis precedes arthritis in 72.7% of cases 1
• Small or patchy psoriatic lesions may occur in scalp or perineum 3
• Nail involvement (pitting, onycholysis) is highly suggestive 1

Enthesitis should be evaluated:

• Inflammation at tendon/ligament insertion sites 1
• Achilles tendon involvement is common 1
• Extensor tendon enthesitis at distal interphalangeal joints shows enthesophytes and calcifications more frequently in PsA 6

Diagnostic Workup

Clinical assessment should include:

• Evaluation for dactylitis across all digits 1
• Assessment of inflammatory features: erythema, warmth, swelling 1
• Morning stiffness duration (typically prominent in inflammatory arthritis) 1
• Rheumatoid factor testing (typically negative in PsA) 1

Imaging recommendations:

• Plain radiographs of hands and wrists as initial imaging 1
• Ultrasound can detect flexor tenosynovitis, peritendon inflammation, and soft tissue edema characteristic of PsA 6, 5
• MRI demonstrates periostitis more frequently in PsA (statistically significant) 4

Clinical Pitfalls

Common diagnostic errors to avoid:

• Dismissing unilateral presentation as "just trauma" when inflammatory features are present 3
• Missing subtle psoriatic lesions in non-exposed areas 3
• Failing to recognize that 14.9% of PsA patients develop arthritis before skin manifestations 1
• Overlooking that up to 50% of PsA patients develop erosions within the first 2 years, indicating this is not a benign condition 3

Prognostic Implications

Early recognition is critical because:

• PsA can cause significant morbidity if inadequately treated 1
• Joint damage occurs early with 11% annual erosion rate in first 2 years 3
• Delay in diagnosis leads to permanent joint destruction 1
• PsA is associated with increased cardiovascular disease and diabetes risk 1