What is the recommended treatment for an adult with uncomplicated hand cellulitis and no significant allergies or underlying conditions?

Treatment for Hand Cellulitis

For uncomplicated hand cellulitis in adults without significant allergies or underlying conditions, treat with oral beta-lactam monotherapy (cephalexin 500 mg four times daily, dicloxacillin 250-500 mg every 6 hours, or amoxicillin) for 5 days if clinical improvement occurs. 1

First-Line Antibiotic Selection

Beta-lactam monotherapy is the standard of care for typical uncomplicated cellulitis, with a 96% success rate, confirming that MRSA coverage is usually unnecessary. 1 The most commonly recommended oral agents include:

• Cephalexin 500 mg every 6 hours 1
• Dicloxacillin 250-500 mg every 6 hours 1
• Amoxicillin (dose varies by severity) 1
• Amoxicillin-clavulanate 875/125 mg twice daily (particularly appropriate for bite-associated cellulitis or traumatic wounds) 1

These agents provide excellent coverage against β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus, which are the primary pathogens in typical cellulitis. 2, 3 In the 15% of cellulitis cases where organisms are identified, most are due to these pathogens. 2

Treatment Duration

Treat for exactly 5 days if clinical improvement has occurred; extend only if symptoms have not improved within this timeframe. 1 This recommendation is supported by high-quality randomized controlled trial evidence showing that 5-day courses are as effective as 10-day courses for uncomplicated cellulitis. 1, 4 A landmark study demonstrated 98% clinical resolution at 14 days with no relapse by 28 days in patients receiving 5 days of therapy. 4

When to Add MRSA Coverage

Do NOT routinely add MRSA coverage for typical nonpurulent hand cellulitis. 1 MRSA is an uncommon cause of typical cellulitis even in high-prevalence settings. 1, 3 However, add MRSA-active antibiotics when specific risk factors are present:

• Penetrating trauma or injection drug use 1
• Purulent drainage or exudate 1
• Evidence of MRSA infection elsewhere or known nasal colonization 1
• Systemic inflammatory response syndrome (SIRS) criteria 1
• Failure to respond to beta-lactam therapy after 48-72 hours 5

If MRSA coverage is needed, recommended regimens include:

• Clindamycin 300-450 mg every 6 hours (covers both streptococci and MRSA as monotherapy) 1
• Trimethoprim-sulfamethoxazole (TMP-SMX) 1-2 DS tablets twice daily PLUS a beta-lactam 1
• Doxycycline 100 mg twice daily PLUS a beta-lactam 1

Critical caveat: Never use doxycycline or TMP-SMX as monotherapy for typical cellulitis, as their activity against β-hemolytic streptococci is unreliable. 1

Essential Adjunctive Measures

• Elevate the affected hand above heart level to promote gravity drainage of edema and inflammatory substances, which hastens improvement. 1
• Examine for and treat predisposing conditions including chronic edema, venous insufficiency, tinea pedis (if involving lower extremity), and any cutaneous lesions. 1, 6
• Assess for abscess formation with ultrasound if there is any clinical uncertainty, as purulent collections require incision and drainage plus MRSA-active antibiotics rather than antibiotics alone. 1

When to Hospitalize

Admit patients with any of the following:

• Systemic inflammatory response syndrome (fever >38°C, tachycardia >90 bpm, hypotension, altered mental status) 1
• Severe immunocompromise or neutropenia 1
• Concern for deeper or necrotizing infection (severe pain out of proportion to examination, skin anesthesia, rapid progression, gas in tissue, bullous changes) 1
• Failure of outpatient treatment after 24-48 hours 1

For hospitalized patients requiring IV therapy, vancomycin 15-20 mg/kg IV every 8-12 hours is first-line (A-I evidence), with alternatives including linezolid 600 mg IV twice daily, daptomycin 4 mg/kg IV once daily, or clindamycin 600 mg IV every 8 hours if local resistance is low. 1, 7

Special Considerations for Hand Cellulitis

Hand cellulitis warrants particular attention for:

• Penetrating trauma history (increases MRSA risk significantly) 5
• Septic arthritis or tenosynovitis (requires urgent surgical consultation) 5
• Deep space infections (may require surgical drainage) 5

Common Pitfalls to Avoid

• Do not reflexively extend treatment to 7-14 days based on residual erythema alone, as some inflammation persists even after bacterial eradication. 1
• Do not add MRSA coverage without specific risk factors, as this represents overtreatment and increases antibiotic resistance. 1
• Do not delay switching therapy if no improvement occurs within 48-72 hours of appropriate first-line antibiotics; consider resistant organisms, cellulitis mimickers, or underlying complications. 5
• Do not use combination therapy when monotherapy is appropriate, as this increases adverse effects without improving outcomes. 1

Monitoring Response

Reassess within 24-48 hours for outpatients to ensure clinical improvement. 1 If warmth and tenderness have resolved, erythema is improving, and the patient is afebrile, stop antibiotics after 5 days. 1 If no improvement in warmth, tenderness, or erythema is observed, extend treatment and reassess for complications. 1