What is the recommended treatment for soft tissue cellulitis?

Treatment of Soft Tissue Cellulitis

For typical cases of cellulitis without systemic signs of infection, a 5-day course of an antimicrobial agent active against streptococci is the recommended treatment, with extension only if the infection has not improved within this time period. 1

Diagnosis Approach

• Cultures of blood or cutaneous aspirates are not routinely recommended for typical cases of cellulitis 1
• Blood cultures should be obtained in specific situations:
  • Patients with malignancy on chemotherapy
  • Neutropenia
  • Severe cell-mediated immunodeficiency
  • Immersion injuries
  • Animal bites
  • Severe systemic features (high fever, hypotension) 1

Antimicrobial Selection Algorithm

Mild Cellulitis (without systemic signs)

• First-line treatment: Antibiotics active against streptococci 1
  • Oral options: penicillin, amoxicillin, dicloxacillin, cephalexin, or clindamycin 1
  • Duration: 5 days (extend only if not improved) 1

Moderate Cellulitis (with systemic signs)

• Treatment: Systemic antibiotics with consideration for MSSA coverage 1
  • Oral options: amoxicillin-clavulanate, cephalexin, clindamycin
  • Parenteral options: nafcillin, cefazolin, clindamycin

Severe Cellulitis (with SIRS or specific risk factors)

• Treatment: Coverage for both MRSA and streptococci 1
  • Risk factors requiring MRSA coverage: penetrating trauma, evidence of MRSA elsewhere, nasal MRSA colonization, injection drug use, purulent drainage 1
  • Options: vancomycin, daptomycin, linezolid, or telavancin (IV) 1
  • For severely compromised patients: vancomycin plus piperacillin-tazobactam or imipenem/meropenem 1

Treatment Setting

• Outpatient: For patients without SIRS, altered mental status, or hemodynamic instability 1
• Inpatient: For patients with:
  • Concern for deeper/necrotizing infection
  • Poor adherence to therapy
  • Severe immunocompromise
  • Failing outpatient treatment 1

Adjunctive Measures

• Elevation of the affected area to promote drainage of edema 1
• Treatment of predisposing factors (edema, underlying cutaneous disorders) 1
• In lower extremity cellulitis, examine interdigital toe spaces and treat fissuring, scaling, or maceration 1
• Systemic corticosteroids (prednisone 40 mg daily for 7 days) may be considered in non-diabetic adults 1

Prevention of Recurrence

• Identify and treat predisposing conditions:
  • Edema, especially lymphedema
  • Obesity
  • Venous insufficiency
  • Prior trauma to the area
  • Tinea pedis or other toe web abnormalities 1
• For patients with 3-4 episodes per year despite treatment of predisposing factors, consider prophylactic antibiotics:
  • Oral penicillin or erythromycin twice daily
  • Intramuscular benzathine penicillin every 2-4 weeks 1

Common Pitfalls and Caveats

1. Overtreatment with broad-spectrum antibiotics: Studies show narrow-spectrum antibiotics targeting streptococci are equally effective for uncomplicated cellulitis 2
2. Excessive treatment duration: 5 days is sufficient for uncomplicated cellulitis with extension only if not improved 1
3. Misdiagnosis: Venous insufficiency, eczema, deep vein thrombosis, and gout are frequently mistaken for cellulitis 3
4. Failure to address underlying conditions: Treating predisposing factors is crucial to prevent recurrence 1
5. Unnecessary MRSA coverage: MRSA is an unusual cause of typical cellulitis unless specific risk factors are present 1

Recent evidence suggests that high-dose cephalexin may result in fewer treatment failures compared to standard dosing, though with slightly more minor adverse effects 4, but more research is needed before this can be recommended as standard practice.