Skin and Soft Tissue Infection (SSTI) - VASP¶
Cellulitis¶
Background¶
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DDx: erysipelas, pyomyositis, necrotizing fasciitis, osteomyelitis, venous stasis, shingles, gout
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Pathogens: Streptococcus species: Group A (most common), B, C, G, Staphylococcus aureus (including MSSA and MRSA)
- Non-purulent, lymphangitis, or erysipelas? Think Streptococcus
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- Purulence (abscess or boil)? Think Staphylococcus
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Unique clinical scenarios and associated organisms/organisms to consider:
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Dog/cat bite: Pasteurella multicoda, Capnocytophaga canimorsus
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Human bite: Eikenella corrodens, oral anaerobes, S. aureus
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Fresh water exposure: Aeromonas hydropholia, Plesiomonas shigelloides
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Saltwater exposure: Vibrio vulnificus
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Neutropenia, presence of ecthyma: Gram negatives (Pseudomonas aeruginosa)
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Immunocompromised: Fungal (Candida spp, Cryptococcus), Nocardia, non-tubercular mycobacteria)
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Burn patients: Pseudomonas, Acinetobacter, Fusarium
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Evaluation¶
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Outline border of erythema and obtain urgent surgery consultation if rapid spread of infection, crepitus, air in tissues or pain dramatically out of proportion to exam
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Blood cultures (BCx): ONLY needed if systemic signs/symptoms of infection or immunocompromised (most pts will not need BCx or imaging)
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Ultrasound for underlying abscess
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CT/MRI w/contrast: if necrotizing fasciitis, pyomyositis or osteomyelitis suspected
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Bilateral lower extremity cellulitis is RARE and warrants further consideration of other non-infectious etiologies
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Elevation test: if erythema improves after elevating leg above the level of the heart for 1-2 minutes, less likely to be infectious cellulitis
Management¶
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Antibiotics for 5 days for uncomplicated; can extend to 10-14 days if little to no improvement, more extensive/serious infection, or if immunosuppressed
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Typically improvement is not seen until >48 hours of antibiotics, usually longer
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Provide anti-Staphylococcal antibiotics for purulent cellulitis in addition to I&D, if abscess present
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Clinical appearance may often appear to worsen initially despite adequate therapy
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Always elevate the extremity for more rapid clinical improvement!
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Mild/Moderate (Outpatient) |
Cephalexin 500 QID Amoxicillin 500 TID Cefadroxil 1g BID |
Cephalexin 500 QID Cefadroxil 1g BID Dicloxacillin 500 QID \*Clindamycin 300-450 q6 |
TMP/SMX 1-2 DS tabs BID Doxycycline 100 BID |
| Severe (Inpatient) | Cefazolin 2g q8h CTX 2g q24h |
Cefazolin 2g q8h Nafcillin 2g q4h |
Vancomycin |
| \*Consider for PCN allergy; check antibiogram (VUMC vs VA) for Staph sensitivities; clindamycin should NOT be used for strep coverage | |||
Necrotizing Fasciitis¶
Background¶
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Infection of the deeper soft tissues that causes necrosis along the muscle fascia and overlying subcutaneous fat that is rapidly progressive and lethal if not addressed
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Clinical cues include rapid spread, pain out of proportion to exam, crepitus and hemorrhagic bullae
Evaluation/Management¶
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SURGICAL EMERGENCY!
- STAT consult to surgical service for emergent debridement (generally EGS vs ortho)
- Imaging does NOT rule out necrotizing fasciitis and should not delay these consultations
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ID consult
- Blood cultures, but this should not delay antibiotic administration
- Contact and droplet precautions x first 24h of abx therapy; after this, contact precautions only if draining or contained wounds
- Vancomycin + either piperacillin-tazobactam 3.375g IV q8h extended infusion OR cefepime 2gm IV q8h + clindamycin 600mg-900mg IV q8h (for antitoxin effects)