Rationale:

• Mild, uncomplicated cellulitis should be treated out of the hospital with oral antibiotics, although it may require surgical drainage which can also be done on an outpatient basis.
• Moderate to severe cellulitis may require hospitalization for observation, surgery, control of comorbidities, and parenteral antibiotics.
• Parenteral antibiotics can be provided at home or in an infusion clinic if the patient is compliant to therapy and the cellulitis is not too severe.

Evidence:

• Classification schemes for cellulitis and soft tissue infection have been reported to assist in treatment decisions (27; 48).
• According to some studies, abscesses <5 cm in diameter may be effectively treated by incision and drainage without the need for systemic antimicrobial therapy (18; 64; 65). More recent studies show no correlation between the size of the abscesses and the relative need for concordant antibiotic therapy (66). Non-purulent cellulitis may be treated with β-lactam antibiotics, lacking activity against MRSA (67). Purulent cellulitis may require antimicrobial agents with activity against MRSA.

Comments:

• Non-purulent cellulitis is usually caused by streptococci, and purulent cellulitis by S. aureus.
• Treatment failure may be due to resistance to the antimicrobial agent, a deeper undrained abscess, or complicating comorbidities such as chronic venous insufficiency or arterial insufficiency.
• In some patients cutaneous inflammation worsens during the initial 24 hours after antimicrobials are begun. This is not necessarily a sign of failure and may merely represent continued local inflammation due to the release of bacterial antigens from antimicrobial activity (18). Anti-inflammatory agents may accelerate resolution of the clinical signs of inflammation (68; 69; 70).