Does cellulitis always require antibiotics?

Management of Cellulitis: When Antibiotics Are Needed

Cellulitis requires antibiotic therapy in virtually all cases, as it is an active bacterial infection of the dermis and subcutaneous tissue that typically requires antimicrobial treatment to resolve and prevent complications. 1

Classification and Treatment Approach

• Typical cases of cellulitis without systemic signs of infection should receive an antimicrobial agent that is active against streptococci, which are the most common causative organisms 1
• For cellulitis with systemic signs of infection (moderate nonpurulent), systemic antibiotics are indicated with consideration for coverage against methicillin-susceptible S. aureus (MSSA) 1, 2
• For severe cases with systemic inflammatory response syndrome (SIRS), penetrating trauma, evidence of MRSA infection elsewhere, or in immunocompromised patients, broader coverage including MRSA-active agents is recommended 1

Antibiotic Selection

• First-line oral therapy for typical non-purulent cellulitis includes beta-lactams such as cephalexin (500 mg four times daily) 2, 3
• Clindamycin is an alternative first-line agent, particularly in penicillin-allergic patients 3
• In areas with high MRSA prevalence, antibiotics with MRSA activity (trimethoprim-sulfamethoxazole, clindamycin) may have higher success rates than cephalexin alone 4
• For severe infections requiring hospitalization, vancomycin plus either piperacillin-tazobactam or a carbapenem is recommended as empiric therapy 1

Duration of Therapy

• The recommended duration of antimicrobial therapy is 5 days for uncomplicated cellulitis 1, 2
• Treatment should be extended if the infection has not improved within the initial 5-day period 1, 5
• Research has shown that 5 days of therapy is as effective as 10 days for uncomplicated cellulitis when clinical improvement has occurred 5

Adjunctive Measures

• Elevation of the affected area is recommended to reduce edema and promote healing 1, 3
• Treatment of predisposing factors such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities is essential 1, 3
• For lower-extremity cellulitis, careful examination of interdigital toe spaces is important as treating fissuring or maceration may reduce recurrence 1, 2
• In non-diabetic adult patients, systemic corticosteroids (prednisone 40 mg daily for 7 days) could be considered to reduce inflammation 1, 2

Special Situations

• Simple abscesses without surrounding cellulitis can be treated with incision and drainage alone without antibiotics 1
• Complex abscesses with significant surrounding cellulitis require both drainage and antibiotic therapy 1
• For recurrent cellulitis (3-4 episodes per year), prophylactic antibiotics such as oral penicillin or erythromycin for 4-52 weeks should be considered 1, 3

Hospitalization Criteria

• Outpatient therapy is appropriate for patients without SIRS, altered mental status, or hemodynamic instability 1, 3
• Hospitalization is recommended for patients with:
  • Concern for deeper or necrotizing infection 1
  • Poor adherence to therapy 1
  • Severe immunocompromise 1, 3
  • Failure of outpatient treatment 1, 2

Common Pitfalls to Avoid

• Don't extend treatment unnecessarily beyond 5 days if clinical improvement has occurred 2, 5
• Don't automatically add MRSA coverage for typical non-purulent cellulitis without specific risk factors 2, 3
• Don't overlook the importance of treating underlying conditions that predispose to recurrent cellulitis 1, 6
• Don't forget to examine interdigital toe spaces in lower-extremity cellulitis 1, 2

Patient Education

• Patients should be educated about potential strategies to prevent recurrence, including enhanced foot hygiene, daily application of emollients, exercise, and weight loss 6
• Many patients are unaware of their risk of recurrence and potential prevention strategies 6