Severe

Characteristics

Immunocompromised
Systemic signs of sepsis with organ dysfunction
Signs of deeper infection (skin sloughing, bullae)

Common Pathogens

Streptococcus pyogenes
(Group A β-hemolytic streptococci)

Methicillin-sensitive S. aureus

Methicillin-resistant S. aureus

Risk factors:

Patients whose cellulitis is associated with penetrating trauma
Evidence of MRSA infection elsewhere
Nasal colonization with MRSA
Injection drug use

Empiric Regimen of Choice

Piperacillin-Tazobactam

AND

Vancomycin

β-Lactam Anaphylaxis

Duration of Therapy

7-10 days, but in general treatment should be extended if the infection has not improved within this time period.