Summary

2014 IDSA update on diagnosis and management of skin and soft tissue infections (SSTIs), updating the 2005 guideline and aligned with IDSA’s MRSA guideline. Stratifies purulent vs nonpurulent SSTIs into mild/moderate/severe categories driving incision-and-drainage and antibiotic selection. Covers impetigo, abscesses, cellulitis/erysipelas, necrotizing fasciitis, pyomyositis, gas gangrene, surgical site infections, animal/human bites, zoonotic SSTIs, and SSTIs in immunocompromised and neutropenic hosts.

Key Recommendations

Incision and drainage is primary therapy for cutaneous abscesses, furuncles, carbuncles, and inflamed epidermoid cysts; antibiotics not needed for simple abscess without SIRS.
Add anti-MRSA antibiotic after I&D when SIRS is present, immunocompromised, failed initial therapy, or severe disease (vancomycin IV; PO doxycycline, clindamycin, or TMP-SMX).
For nonpurulent cellulitis without systemic signs, use an agent active against streptococci (e.g., penicillin, cephalexin, dicloxacillin); routine MRSA coverage not required.
For severe nonpurulent cellulitis or suspected necrotizing infection, empiric vancomycin PLUS piperacillin-tazobactam (or carbapenem, or ceftriaxone + metronidazole).
Documented group A streptococcal necrotizing fasciitis: penicillin PLUS clindamycin; urgent surgical debridement is the primary intervention.
Treat cellulitis for 5 days, extending only if not improving; elevate limb and treat predisposing factors (tinea pedis, edema, venous insufficiency).
Prophylactic penicillin or erythromycin BID (or IM benzathine penicillin q2–4 wk) for patients with ≥3–4 cellulitis episodes/year despite addressing predisposing factors.
Bullous and nonbullous impetigo: topical mupirocin or retapamulin BID × 5 days; oral therapy (dicloxacillin or cephalexin × 7 days) if numerous lesions or outbreaks.
Animal bite preemptive antibiotics (3–5 days of amoxicillin-clavulanate) for immunocompromised, asplenic, advanced liver disease, edema, hand/face injuries, or deep penetrating wounds; close only facial bites.
Update tetanus toxoid (Tdap preferred) if last dose >10 yr (or >5 yr for dirty wounds); consider rabies postexposure prophylaxis.
Pyomyositis: MRI is preferred imaging; empiric vancomycin with drainage; cefazolin or antistaphylococcal penicillin once MSSA confirmed; treat 2–3 weeks.
Clostridial myonecrosis: emergent surgical debridement plus penicillin PLUS clindamycin; hyperbaric oxygen NOT recommended.
Febrile neutropenia with SSTI: hospitalize and start vancomycin PLUS antipseudomonal beta-lactam (cefepime, carbapenem, or piperacillin-tazobactam); add empiric antifungal if fever persists 4–7 days.
Surgical site infection: suture removal and I&D are primary; add antibiotics only if erythema >5 cm, T >38.5°C, HR >110, or WBC >12,000/µL; choose agent based on operation site.
Cat scratch disease: azithromycin 500 mg day 1 then 250 mg × 4 days (>45 kg); bacillary angiomatosis: erythromycin or doxycycline for 2 weeks to 2 months.

Thresholds & Doses

SIRS criteria triggering antibiotics in purulent SSTI: T >38°C or <36°C, RR >24, HR >90, WBC >12,000 or <400 cells/µL.
Severe SSTI criteria (Figure 1): failed I&D + oral abx, SIRS, immunocompromised, or signs of deeper infection (bullae, hypotension, organ dysfunction).
Impetigo topical: mupirocin or retapamulin BID × 5 days; oral × 7 days (dicloxacillin 250 mg QID or cephalexin 250 mg QID).
MSSA SSTI: nafcillin/oxacillin 1–2 g IV q4h; cefazolin 1 g IV q8h; dicloxacillin 500 mg PO QID; cephalexin 500 mg PO QID.
MRSA SSTI: vancomycin 30 mg/kg/day IV in 2 divided doses (trough 15–20 µg/mL severe); linezolid 600 mg q12h; daptomycin 4 mg/kg q24h; clindamycin 600 mg IV q8h or 300–450 mg PO QID; doxycycline 100 mg PO BID; TMP-SMX 1–2 DS tabs BID.
Cellulitis duration: 5 days, extended if not improving.
Surgical site infection antibiotic triggers: erythema/induration >5 cm from wound edge, T >38.5°C, HR >110, WBC >12,000/µL.
Cellulitis prophylaxis: oral penicillin or erythromycin BID for 4–52 weeks, or IM benzathine penicillin q2–4 weeks, for ≥3–4 episodes/year.
Cutaneous anthrax: penicillin V 500 mg PO QID × 7–10 days (natural); ciprofloxacin 500 mg PO BID or levofloxacin 500 mg daily × 60 days (bioterrorism).
Cat scratch disease azithromycin: >45 kg → 500 mg day 1, then 250 mg × 4 days; <45 kg → 10 mg/kg day 1, then 5 mg/kg × 4 days.
Erysipeloid: penicillin 500 mg QID or amoxicillin 500 mg TID × 7–10 days.
Bubonic plague: streptomycin 15 mg/kg IM q12h, or doxycycline 100 mg PO BID; gentamicin as alternative.
Tularemia: streptomycin 15 mg/kg IM q12h or gentamicin 1.5 mg/kg IV q8h (severe); doxycycline 100 mg BID or tetracycline 500 mg QID (mild); duration ≥14 days.
Neutropenia definition: ANC <500 cells/µL or expected to fall <500 within 48 h; high risk = prolonged neutropenia >7 days with ANC <100 or MASCC <21.
Febrile neutropenia SSTI treatment duration: 7–14 days.
Candida SSTI: echinocandin first-line; treat 2 weeks after blood clearance/lesion resolution.
Aspergillus SSTI: voriconazole (6 mg/kg IV q12h × 2 then 4 mg/kg q12h); duration 6–12 weeks.
Corticosteroid adjunct option for cellulitis in nondiabetic adults: prednisone 40 mg daily × 7 days.
Tetanus booster: give if >10 years for clean wounds, >5 years for dirty wounds; Tdap preferred over Td if not previously given.

Citations

Figure 1 — Algorithm stratifying purulent vs nonpurulent SSTIs into mild/moderate/severe with empiric regimens.
Figure 2 — Surgical site infection management algorithm with 5-cm erythema and fever thresholds.
Table 2 — Antibiotic doses for impetigo, MSSA, and MRSA SSTIs (adult and pediatric).
Table 4 — Treatment of necrotizing infections (mixed, streptococcal, staphylococcal, clostridial, Aeromonas, Vibrio).
Table 5 — Recommended therapy for animal and human bite infections.
Recommendations 27–29 — Necrotizing fasciitis: surgical consult, broad empiric coverage, penicillin + clindamycin for GAS.
Recommendations 40–44 — Animal bite preemptive therapy, infected bite treatment, tetanus, and wound closure.
Recommendations 63–72 — SSTI management in febrile neutropenia (initial and persistent episodes).