Management of Cellulitis with Abscess
Incision and drainage is the cornerstone of treatment for cellulitis with abscess, and the presence of significant surrounding cellulitis mandates adjunctive antibiotic therapy—this dual approach is essential and distinguishes this condition from simple abscesses that require drainage alone. 1
Immediate Procedural Management
Perform incision and drainage emergently if any of the following are present: 1
- Systemic signs of infection or sepsis
- Immunosuppression
- Diabetes mellitus
- Diffuse cellulitis extending beyond abscess borders
The incision must provide adequate drainage while minimizing complications. For perianal locations, keep the incision as close as possible to the anal verge to minimize fistula tract length. 1
Antibiotic Therapy: When and What
Indications for Antibiotics
The presence of significant cellulitis surrounding the abscess is an absolute indication for antibiotics, unlike simple abscesses where drainage alone suffices. 2, 1 Additional indications include: 1
- Systemic signs of infection (fever, SIRS)
- Immunocompromised state
- Incomplete source control after drainage
- Diabetes mellitus
Antibiotic Selection Algorithm
For mild-to-moderate cases without MRSA risk factors:
- First-line oral agents: Cephalexin, dicloxacillin, amoxicillin-clavulanate, or clindamycin 1
- These target streptococci and methicillin-sensitive Staphylococcus aureus (MSSA), the most common pathogens 2
For cases with MRSA risk factors (penetrating trauma, injection drug use, purulent drainage, known MRSA colonization, or SIRS):
- Dual coverage required: Vancomycin, daptomycin, linezolid, or telavancin for inpatient management 2
- Oral options: Clindamycin alone (covers both streptococci and MRSA), or combine trimethoprim-sulfamethoxazole or doxycycline with a beta-lactam 2
For severely compromised patients:
- Broad-spectrum empiric coverage: Vancomycin plus piperacillin-tazobactam or imipenem-meropenem 2
- This covers gram-positive, gram-negative, and anaerobic organisms 1
Antibiotic Duration
5-7 days is sufficient if clinical improvement occurs by day 5 2, 1. Extend to 7-14 days for more severe infections or if improvement is inadequate. 2, 1 This shorter duration is supported by high-quality evidence showing 5-day courses are as effective as 10-day courses when improvement is documented. 2
Adjunctive Measures
Elevation of the affected area is essential to promote gravity drainage of edema and inflammatory substances. 2
Address predisposing factors: 2
- For lower extremity cellulitis, carefully examine interdigital toe spaces
- Treat tinea pedis, fissuring, scaling, or maceration to eradicate pathogen colonization
- Manage underlying venous insufficiency, lymphedema, or eczema
Disposition: Inpatient vs Outpatient
Hospitalize if any of the following are present: 2, 1
- SIRS or sepsis
- Hemodynamic instability or altered mental status
- Severe immunocompromise
- Concern for deeper or necrotizing infection
- Poor adherence to outpatient therapy
Outpatient management is appropriate for patients without systemic signs, with stable vital signs, and reliable follow-up. 2
Culture Considerations
Cultures are not routinely recommended for typical cellulitis with abscess. 2 However, obtain blood cultures and consider tissue cultures in: 2
- Malignancy on chemotherapy
- Neutropenia
- Severe cell-mediated immunodeficiency
- Immersion injuries or animal bites
- Recurrent abscesses (culture early and treat based on pathogen isolated) 2
Common Pitfall
Do not assume MRSA is the primary pathogen in typical cellulitis. Beta-lactam monotherapy (cefazolin, oxacillin) is successful in 96% of cellulitis cases, even in settings with high MRSA prevalence for other infections. 2 Reserve MRSA coverage for specific risk factors outlined above to avoid unnecessary broad-spectrum antibiotic use.