From the Guidelines

Treatment for cellulitis in an inpatient setting typically involves antibiotics active against streptococci and MRSA.

For patients with nonpurulent cellulitis, a 5- to 6-day course of antibiotics active against streptococci is recommended 1.
For patients with systemic signs of infection, vancomycin or another antimicrobial effective against both MRSA and streptococci is recommended 1.
Elevation of the affected area and treatment of predisposing factors are also recommended 1.

Cephalosporin, penicillin, or clindamycin are recommended for typical cases of cellulitis without systemic signs of infection 1.
Vancomycin plus either piperacillin-tazobactam or imipenem-meropenem is recommended as a reasonable empiric regimen for severe infection 1.

The recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period 1.
A 5- to 7-day course of antibiotics is also recommended by the National Institute for Health and Care Excellence (NICE) guideline 1.

From the Research

The treatment of cellulitis in an inpatient setting typically involves the use of intravenous antibiotics, with the goal of covering Streptococcus and methicillin-sensitive Staphylococcus aureus 2.
The choice of antibiotic should be based on the patient's risk factors and regional susceptibility patterns, with consideration for methicillin-resistant Staphylococcus aureus (MRSA) in cases with specific risk factors 2, 3.
A 5-day course of treatment is often sufficient, but may need to be extended if symptoms do not improve 2.
Addressing predisposing factors, such as lymphedema, venous stasis, and deep vein thrombosis, can help minimize the risk of recurrence 2, 4.

A cost analysis study found that outpatient parenteral antibiotic therapy (OPAT) was significantly less expensive than hospital admission for the treatment of cellulitis, with a mean total cost of $2170 vs. $10,145 5.
However, the study also found that a dedicated OPAT clinic was more expensive than a "return to ED" approach, highlighting the need for flexible and tailored treatment options 5.
Patients with cellulitis may be able to receive treatment in an outpatient setting, provided they have adequate information and support, and are able to manage their condition effectively 6.

Cellulitis can be difficult to diagnose due to the presence of non-infectious clinical mimickers, such as venous stasis dermatitis, contact dermatitis, and lymphedema 4.
A clinical diagnosis based on history and physical examination is often necessary, as microbiological diagnosis may be unobtainable due to poor sensitivity of culture specimens 4.
Awareness of common myths and misconceptions regarding cellulitis can help guide providers in clinical decision making and avoid treatment errors 3.