I have a subcutaneous, fluctuating, tender, bruised‑purple swelling about the size of half a baseball above my elbow that appeared after a venipuncture, worsens throughout the day, resolves by morning, has an itchy erythematous rim, and is not associated with fever, warmth, paresthesia, or limited motion; what is the likely diagnosis and appropriate management?

Post-Venipuncture Hematoma with Inflammatory Changes

This is a post-venipuncture hematoma with secondary inflammatory reaction (superficial thrombophlebitis), not an infection requiring antibiotics. The key distinguishing features—absence of fever, warmth, progressive worsening, or systemic symptoms—rule out cellulitis or abscess formation that would mandate antimicrobial therapy 1.

Clinical Reasoning

Why This Is NOT an Infection

The clinical presentation lacks critical features of true infection:

• No heat or warmth at the site excludes cellulitis, which characteristically presents with local warmth, progressive erythema, and often systemic signs 1, 2
• No fever and absence of systemic toxicity argue strongly against bacterial infection requiring antibiotics 1
• Fluctuating nature (worse during day, baseline by morning) is inconsistent with progressive bacterial infection, which would worsen continuously 1
• Itchy erythematous border suggests inflammatory/allergic reaction rather than infectious cellulitis 2

Diagnosis: Post-Venipuncture Hematoma with Superficial Thrombophlebitis

• The "sack of fluid" sensation on palpation combined with the purple/red discoloration and tenderness is classic for organized hematoma 3, 4
• Venipuncture trauma (poked 3 times) caused vessel injury leading to blood accumulation in subcutaneous tissue 4
• The circular erythematous border and itching represent inflammatory response to blood breakdown products and possible superficial thrombophlebitis 1, 5
• Fluctuation throughout the day (swelling increases with arm dependency, resolves with overnight elevation) is pathognomonic for fluid collection without infection 6

Management Algorithm

Immediate Conservative Management (First-Line)

1. Elevation and compression

   • Elevate arm above heart level multiple times daily 6
   • Apply compression wrap when arm is dependent 6
   • This addresses the gravitational fluid accumulation explaining the diurnal variation 6

2. Warm compresses

   • Apply 15-20 minutes, 3-4 times daily to promote resorption 4

3. NSAIDs for inflammation

   • Ibuprofen 400-600 mg three times daily for 5-7 days to reduce inflammatory response 4, 5

When to Escalate: Aspiration or Drainage

Consider needle aspiration if:

• Hematoma persists beyond 2-3 weeks despite conservative measures 4
• Size continues to increase rather than stabilize 4
• Skin overlying the hematoma becomes taut, shiny, or shows signs of impending necrosis 4

Technique: Aspiration under sterile technique with local anesthesia can be performed in outpatient setting 4

Red Flags Requiring Urgent Evaluation

Seek immediate medical attention if any develop:

• Fever >38.5°C or systemic symptoms (would indicate superimposed infection) 1
• Increasing warmth at the site (suggests evolving cellulitis) 1, 2
• Woody-hard induration (could indicate necrotizing process) 7
• Skin necrosis or bullae formation (indicates tissue ischemia from pressure) 4
• Progressive pain out of proportion to examination findings 1

What NOT to Do

Antibiotics Are NOT Indicated

• No purulent drainage, no warmth, no fever means antibiotics provide no benefit and risk unnecessary side effects 1
• The IDSA guidelines are explicit: erythema around a wound without other infectious signs does not constitute cellulitis requiring antibiotics 1, 2
• Even if this were a superficial surgical site infection, antibiotics would only be indicated with temperature >38.5°C, heart rate >110, or erythema extending >5 cm beyond margins 1

Avoid Premature Drainage

• Organized hematomas often resorb spontaneously with conservative management 3, 4
• Unnecessary aspiration increases infection risk 1

Expected Timeline

• Weeks 1-2: Gradual reduction in size and tenderness with conservative measures 4
• Weeks 2-4: Progressive resolution of discoloration (purple→green→yellow as hemoglobin breaks down) 5
• Beyond 4 weeks: If no improvement, consider aspiration or surgical consultation for chronic expanding hematoma 3

Common Pitfall to Avoid

The most common error is misdiagnosing this as cellulitis and prescribing unnecessary antibiotics. The absence of warmth and fever are your clinical anchors—these features are nearly universal in true bacterial cellulitis and their absence should redirect you away from infectious etiologies 1, 2.