What is the differential diagnosis for a patient with right hand swelling, pain, and redness, without fever, of unknown age and medical history?

Differential Diagnosis for Right Hand Swelling, Pain, and Redness Without Fever

Most Likely Diagnoses to Consider First

The most critical initial step is to exclude life-threatening necrotizing soft tissue infections and septic conditions, even in the absence of fever, as systemic toxicity can be absent early in the disease course. 1

Infectious Etiologies

Cellulitis remains the primary consideration for unilateral hand swelling with pain and redness, even without fever, as systemic signs may be absent in early or localized infection. 2 Key features include:

• Progressive swelling over days following minor trauma
• Erythema that may extend proximally into the forearm
• Warmth and tenderness on palpation
• History of recent skin breach or injury 2

Necrotizing fasciitis or toxic shock-like syndrome from Group A Streptococcus must be urgently excluded, as these can present with hand/forearm swelling and redness before systemic signs develop. 1 Critical distinguishing features include:

• Tense swelling with severe pain disproportionate to examination findings
• Rapid progression over hours to days
• Presence of bullae or skin necrosis
• Even transient hypotension warrants immediate surgical consultation 1

Atypical mycobacterial infection (Mycobacterium bovis or other species) should be considered, particularly with:

• Painless or minimally painful swelling extending from hand to forearm
• Subacute course over weeks
• History of remote trauma to the same hand
• General malaise without high fever 3

Traumatic/Mechanical Etiologies

Occult fracture, particularly of metacarpal bases, requires evaluation with appropriate imaging:

• History of direct trauma (punching, crush injury, car door closure)
• Localized swelling over metacarpophalangeal joints
• Standard radiographs may miss fractures; oblique views are essential 4
• Pain with axial loading or range of motion testing 4

Vascular access-related complications (if patient has dialysis access):

• Steal syndrome presents with hand pain, coldness, and swelling
• Can occur months to years after access creation
• Digital blood pressure measurement and Doppler ultrasound are diagnostic 5

Inflammatory/Rheumatologic Conditions

Hand, Foot, and Mouth Disease (HFMD) in adults presents with:

• Vesicular lesions on palms evolving from pink macules
• Oral lesions with painful ulcers
• Low-grade fever or fever may be absent in adults
• Distinguish from other vesicular eruptions by characteristic distribution 6, 7

Incomplete Kawasaki Disease should be considered if:

• Erythema and edema of hands without vesicles
• Fever duration ≥5 days (though may have resolved by presentation)
• Presence of 2-3 other principal features (conjunctival injection, oral changes, rash elsewhere, lymphadenopathy)
• Requires echocardiography if suspected 5

Drug-Related Causes

Red puffy hand syndrome from intravenous drug use:

• Bilateral, painless, non-pitting erythema and edema of dorsal hands
• Fixed appearance over months to years
• History of IV drug use (may be remote)
• Lymphatic blockage from drug toxicity or infection complications 8

Critical Differentials Requiring Immediate Exclusion

Rocky Mountain Spotted Fever and Meningococcemia must be excluded when palmar-plantar rash is present:

• RMSF: blanching pink macules evolving to petechiae (not vesicles), mortality 5-10% if untreated, requires immediate doxycycline 7
• Meningococcemia: rapidly progressive petechial/purpuric rash within hours, requires emergent ceftriaxone 7

Diagnostic Approach

Immediate Assessment

• Evaluate for systemic toxicity: tachycardia, hypotension, altered mental status (even without fever) 1
• Assess pain severity relative to examination findings (severe pain with minimal findings suggests necrotizing infection) 1
• Document progression timeline: hours suggests necrotizing infection, days suggests cellulitis, weeks suggests mycobacterial or chronic process 3, 2

Physical Examination Specifics

• Palpate for fluctuance, crepitus, or tense compartments 1
• Check for vesicular lesions on palms, soles, and oral mucosa 6, 7
• Examine for conjunctival injection, oral mucosal changes, and lymphadenopathy 5
• Assess vascular status: pulses, capillary refill, temperature differential 5
• Look for injection track marks or scarring 8

Initial Imaging

• Plain radiographs with oblique views to exclude fracture 4
• Ultrasound can identify abscess, tenosynovitis, or joint effusion 5
• CT or MRI if deep space infection or necrotizing fasciitis suspected 5

Laboratory Evaluation

• Complete blood count, CRP, ESR (elevated in infection and Kawasaki disease) 5
• Blood cultures if systemic infection suspected 1
• Aspirate fluid for Gram stain and culture if abscess present 1
• Consider mycobacterial cultures if subacute presentation 3

Common Pitfalls to Avoid

• Do not dismiss infection based solely on absence of fever—elderly, immunocompromised, or patients with localized infection may be afebrile 3, 2
• Do not delay surgical consultation if necrotizing infection cannot be excluded; immediate debridement is lifesaving 1
• Do not rely on standard radiographs alone for metacarpal base fractures; obtain oblique views 4
• Do not attribute bilateral hand findings to rheumatoid arthritis without excluding red puffy hand syndrome in patients with IV drug use history 8
• Do not exclude Kawasaki disease based on fever resolution; diagnosis can be made retrospectively with careful history 5