Management and Duration of Cellulitis Treatment
The recommended duration of antimicrobial therapy for cellulitis is 5 days, but treatment should be extended if the infection has not improved within this time period. 1
Diagnosis Approach
- Cultures of blood or cutaneous aspirates, biopsies, or swabs 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
- Patients with severe systemic features (high fever, hypotension) 1
Antimicrobial Selection
Mild Cellulitis (without systemic signs)
- Use an antimicrobial agent active against streptococci 1
- Suitable oral options include:
- Penicillin
- Amoxicillin
- Amoxicillin-clavulanate
- Dicloxacillin (125-250 mg every 6 hours) 2
- Cephalexin
- Clindamycin
Moderate Cellulitis (with systemic signs)
- Systemic antibiotics covering streptococci are indicated
- Consider coverage against methicillin-susceptible S. aureus (MSSA) 1
Severe Cellulitis (with SIRS or high-risk factors)
- Cover both MRSA and streptococci if:
- Associated with penetrating trauma
- Evidence of MRSA infection elsewhere
- Nasal colonization with MRSA
- Injection drug use
- Purulent drainage
- Presence of SIRS 1
- Options include:
- IV: Vancomycin, daptomycin, linezolid (600 mg IV or oral q12h) 3, or telavancin
- Oral: Doxycycline, clindamycin, or trimethoprim-sulfamethoxazole
For Severely Compromised Patients
- Broad-spectrum coverage may be needed
- Vancomycin plus either piperacillin-tazobactam or imipenem/meropenem is recommended 1
Treatment Duration and Setting
Duration
- 5 days of antimicrobial therapy is recommended for uncomplicated cases 1
- Extend treatment if infection has not improved within 5 days 1
- For severe staphylococcal infections, therapy should continue for at least 14 days 2
Treatment Setting
- Outpatient therapy for patients without SIRS, altered mental status, or hemodynamic instability 1
- Hospitalization recommended if:
- Concern for deeper or necrotizing infection
- Poor adherence to therapy
- Severely immunocompromised patient
- Outpatient treatment is failing 1
Adjunctive Measures
- Elevate the affected area to promote gravity drainage of edema 1
- Treat predisposing factors:
- Edema
- Underlying cutaneous disorders
- In lower extremity cellulitis, examine interdigital toe spaces for fissuring, scaling, or maceration 1
- Consider systemic corticosteroids (prednisone 40 mg daily for 7 days) in nondiabetic adult patients 1
Management of Recurrent Cellulitis
- Identify and treat predisposing conditions:
- For patients with 3-4 episodes per year despite addressing predisposing factors, consider prophylactic antibiotics:
- Oral penicillin or erythromycin twice daily for 4-52 weeks
- Intramuscular benzathine penicillin every 2-4 weeks 1
- Consider a 5-day decolonization regimen for recurrent S. aureus infections:
- Intranasal mupirocin twice daily
- Daily chlorhexidine washes
- Daily decontamination of personal items (towels, sheets, clothes) 1
Common Pitfalls and Caveats
- MRSA is an unusual cause of typical cellulitis; coverage is not routinely needed unless specific risk factors are present 1
- Conditions frequently mistaken for cellulitis include venous insufficiency, eczema, deep vein thrombosis, and gout 5
- For combination therapy targeting both streptococci and MRSA, clindamycin alone or trimethoprim-sulfamethoxazole/doxycycline plus a β-lactam can be used 1
- Recurrence rates are high (8-20% annually), especially in patients with persistent risk factors 1, 4
- Addressing underlying conditions is crucial to prevent recurrences, as the risk increases with each episode 4