From the Guidelines
Streptococcal cellulitis typically presents with a bright red, well-demarcated, rapidly spreading erythema, while staphylococcal cellulitis appears more localized with a deeper red or purplish color and less distinct borders, and is more likely to form abscesses or have purulent drainage. The clinical differences between strep and staph cellulitis are crucial for guiding treatment decisions. Streptococcal cellulitis often has a sharp, distinct border and may be accompanied by lymphangitis and regional lymphadenopathy, whereas staphylococcal infections are frequently associated with folliculitis and may have purulent drainage 1.
Key Clinical Features
- Streptococcal cellulitis:
- Bright red, well-demarcated, rapidly spreading erythema
- Sharp, distinct border
- Lymphangitis and regional lymphadenopathy
- Fever common
- Staphylococcal cellulitis:
- More localized, deeper red or purplish color
- Less distinct borders
- Abscesses, pustules, or furuncles
- Central necrotic area
- Frequently associated with folliculitis and purulent drainage
Treatment Considerations
Treatment for streptococcal cellulitis typically involves penicillins, such as penicillin V 500mg four times daily for 7-10 days, while staphylococcal infections often require coverage for MRSA with medications like trimethoprim-sulfamethoxazole or clindamycin 1. The choice of antibiotic should be guided by the severity of the infection, the presence of systemic signs, and the likelihood of MRSA involvement. For typical cases of cellulitis without systemic signs of infection, an antimicrobial agent active against streptococci is recommended, while for cases with systemic signs or risk factors for MRSA, broader coverage may be necessary.
Management Principles
- Elevation of the affected area to promote gravity drainage of edema and inflammatory substances
- Treatment of underlying conditions that may have predisposed to the infection, such as tinea pedis or venous eczema
- Consideration of systemic corticosteroids as an adjunct for treatment of uncomplicated cellulitis and erysipelas in selected adult patients
- Measures to reduce recurrences of cellulitis, including treating interdigital maceration, keeping the skin well hydrated, and reducing underlying edema.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Clinical Differences between Strep and Staph Cellulitis
- The majority of cases of cellulitis are nonculturable, and therefore the causative bacteria are unknown 2.
- In the 15% of cellulitis cases in which organisms are identified, most are due to β-hemolytic Streptococcus and Staphylococcus aureus 2.
- The diagnosis of cellulitis is based primarily on history and physical examination, and treatment of uncomplicated cellulitis should be directed against Streptococcus and methicillin-sensitive S. aureus 2, 3.
Treatment of Cellulitis
- Five days of treatment is sufficient with extension if symptoms are not improved 2.
- Antibiotics with activity against community-associated MRSA, such as trimethoprim-sulfamethoxazole and clindamycin, are preferred empiric therapy for outpatients with cellulitis in the community-associated MRSA-prevalent setting 4.
- The addition of trimethoprim-sulfamethoxazole to cephalexin did not improve outcomes overall or by subgroup in patients diagnosed with cellulitis without abscess 5, 6.
- Coverage for non-purulent cellulitis is generally not recommended, even with rising rates of community-acquired methicillin-resistant Staphylococcus aureus 3.
Risk Factors and Complications
- Risk factors for treatment failure include therapy with an antibiotic that was not active against community-associated MRSA and severity of cellulitis 4.
- Factors associated with treatment failure also include specific risk factors such as athletes, children, men who have sex with men, prisoners, military recruits, residents of long-term care facilities, those with prior MRSA exposure, and intravenous drug users 2.
- Underlying complicating conditions such as immunosuppression, chronic liver disease, or chronic kidney disease can also affect treatment outcomes 2.