Suspected skin or soft tissue infection (adult)
Red, warm, swollen, painful skin. Adults only; children need a paediatric guideline.
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Infectious DiseaseManagement
Cellulitis & Skin/Soft Tissue Infection Management (IDSA 2014)
Cellulitis & Skin/Soft Tissue Infection Management (IDSA 2014): Suspected skin or soft tissue infection (adult) → Assess severity, type and mimics → Red...
Pathway Overview
21 steps
Algorithm Steps
21 total
01Start 02Action Assess severity, type and mimics
Check vital signs first: look for sepsis and necrotising infection.
- Systemic signs: temperature >38°C or <36°C, heart rate >90/min, respiratory rate >24/min, abnormal white cell count, hypotension or confusion
- Purulent: abscess, furuncle, carbuncle or pus. Non-purulent: cellulitis or erysipelas with no pus
- Mark the edge of the redness to track spread
- Consider mimics: DVT, gout, venous stasis dermatitis, contact dermatitis
03Decision Red flags for necrotising infection?
Pain out of proportion, rapid spread, hard wooden tissue, oedema beyond the redness, crepitus, bullae, skin necrosis or bruising, systemic toxicity.
- If Yes
04Warning Necrotising infection suspected: emergency surgical review now
Surgical exploration confirms the diagnosis. CT or MRI must not delay surgery.
- Call the surgical team now for exploration and debridement
- Resuscitate and treat as sepsis: follow the sepsis pathway
- Start IV antibiotics at once (next step); do not wait for imaging
05Action Necrotising infection: broad IV antibiotics plus surgery (adult)
Adult doses. Children: seek specialist advice.
- Meropenem 1 g IV 8-hourly PLUS vancomycin IV PLUS clindamycin 600 mg IV 8-hourly
- Vancomycin (adult): load 25–30 mg/kg IV (max 2.5 g), then 15–20 mg/kg IV (max 2 g) 12-hourly; actual body weight; less often in renal impairment; monitor levels
- Wound immersed in fresh water or seawater: add ciprofloxacin 400 mg IV 8-hourly
- Consider IV immunoglobulin: discuss with the infectious diseases team
- Follow the necrotising soft tissue infection pathway
06Outcome Admit: repeat surgery every 24–36 h until no more debridement needed
Continue antibiotics until no more debridement is needed, the patient improves and fever has gone for 48–72 h.
If No07Warning Before antibiotics: groups that need a different plan
Children, bites, water-exposed wounds, diabetic foot, periorbital or orbital cellulitis, neutropenia, severe immunocompromise, penicillin allergy.
- Children: weight-based doses from a paediatric guideline (for example RCH Melbourne)
- Bite, water-exposed wound, diabetic foot, periorbital or orbital cellulitis, neutropenia: use the specific pathway
- Penicillin allergy, not life-threatening: cefalexin or cefazolin. Life-threatening (anaphylaxis, severe skin reaction): clindamycin 300–450 mg orally 6-hourly or vancomycin IV
08Decision Non-purulent (cellulitis or erysipelas, no pus)?
- If Yes
- Non-purulent
09Action Non-purulent cellulitis: beta-lactam against streptococci
Streptococci cause most cases. MRSA is an unusual cause of typical cellulitis.
- A beta-lactam alone treats typical cellulitis; adding TMP-SMX gives no extra benefit
- Elevate the limb. Treat oedema, tinea and toe-web fissures
- Unilateral leg swelling: consider DVT
10Decision MRSA risk factors?
Prior MRSA infection or colonisation, MRSA elsewhere, injection drug use, penetrating trauma, recent hospitalisation, Aboriginal and Torres Strait Islander or Pacific Islander people, or a high-MRSA area (for example NT, remote north Queensland, US community).
- If Yes
11Warning Before TMP-SMX or doxycycline: pregnancy, potassium, warfarin
Check these before you choose an oral MRSA-active antibiotic.
- Pregnancy: use clindamycin. Avoid TMP-SMX and doxycycline
- TMP-SMX: can raise potassium (CKD, ACE inhibitor, ARB, spironolactone, older age) and INR (warfarin); avoid with methotrexate
- Children: no doxycycline under 8 years; use weight-based doses
12Action MRSA risk: use an MRSA-active antibiotic (adult)
Oral options for mild infection. Vancomycin IV for moderate or severe infection.
- Oral: TMP-SMX 160/800 mg 1–2 tablets 12-hourly OR doxycycline 100 mg 12-hourly OR clindamycin 300–450 mg 6-hourly
- Non-purulent: TMP-SMX and doxycycline do not reliably cover streptococci. Add one to the beta-lactam, or use clindamycin alone
- Moderate or severe: vancomycin IV (dose in the moderate-severe step)
- Adjust to culture results and local susceptibility
13Decision Moderate or severe infection?
Systemic signs, hypotension, confusion, severe immunocompromise, failed oral therapy, poor adherence or cannot take oral medicines.
- If Yes
- Moderate-severe
14Action Moderate-severe: admit for IV antibiotics (adult)
Purulent infection, suspected S. aureus or failed oral beta-lactam: add vancomycin IV. Switch to oral when improving.
- Flucloxacillin 2 g IV 6-hourly OR cefazolin 2 g IV 8-hourly
- Add vancomycin IV if: MRSA risk, purulent infection, S. aureus suspected or failed oral beta-lactam. Life-threatening penicillin allergy: vancomycin IV alone
- Vancomycin (adult): load 25–30 mg/kg IV (max 2.5 g), then 15–20 mg/kg IV (max 2 g) 12-hourly; actual body weight; less often in renal impairment; monitor levels
- Hypotension, septic shock or rapid spread: treat as necrotising infection and call surgery
- Blood cultures if sepsis, neutropenia or severe immunocompromise
- Adjust TMP-SMX and cefazolin to renal function
15Action Reassess at 48–72 hours
Redness can worsen for a short time after antibiotics start. Compare with the marked border.
- Check temperature, heart rate, pain and spread beyond the marked border
- Review culture results and adjust the antibiotic
16Decision Improving?
- If Yes
17Outcome Improving: finish 5 days in total (up to 10 if severe); IV to oral when able
Treat predisposing factors (oedema, tinea, venous disease). 3–4 episodes a year: consider penicillin prophylaxis.
If No18Warning Not improving: re-evaluate now
Look for an abscess, necrotising infection, resistant organism or another diagnosis.
- Look for an abscess (ultrasound) and drain it; recheck the necrotising red flags
- Review the diagnosis: DVT, gout, stasis dermatitis, drug reaction
- Culture; cover MRSA if not covered; change oral to IV
19Outcome Escalate: admit for IV antibiotics; seek infectious diseases or surgical advice
Extend treatment beyond 5 days until improved.
If No- Mild
20Action Mild (no systemic signs): oral antibiotic at home, 5 days (adult)
Review in 48–72 hours. Return at once if the redness spreads fast, fever starts or pain becomes severe.
- Flucloxacillin 500 mg orally 6-hourly OR cefalexin 500 mg orally 6-hourly
- MRSA risk: use the oral option from the MRSA step
- Drained abscess with no antibiotic indication: no antibiotic
- Extend beyond 5 days only if not improved
- Path rejoins step 15Shared downstream outcome
If No- Path rejoins step 13Shared downstream outcome
If No- Purulent
21Action Purulent: incision and drainage
Drainage is the main treatment. Many drained abscesses need no antibiotic.
- Incision and drainage of the abscess, carbuncle or large furuncle
- Add an antibiotic if: systemic signs, immunocompromise, spreading cellulitis, large or multiple abscesses, critical site (for example face or hand), very young or old, or no response to drainage
- Culture the pus if an antibiotic is given or the abscess recurs
- Recurrent abscess at one site: look for pilonidal cyst, hidradenitis or a foreign body
- Path rejoins step 10Shared downstream outcome
Guideline Source
IDSA Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update (Stevens DL et al., Clin Infect Dis 2014;59:e10-e52)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults only. Children need weight-based doses from a paediatric guideline.
- MRSA rates differ by region. Use local susceptibility data (Australia: Therapeutic Guidelines: Antibiotic).
- Bites, water-exposed wounds, diabetic foot, orbital cellulitis and neutropenia need specific pathways.
- Doses assume normal renal function; adjust vancomycin and TMP-SMX in renal impairment.
- Surgical site infections and pyomyositis are not covered; use a specific guideline.
Contraindicated Populations
Children (adult doses only)Neutropenia or severe immunocompromiseDiabetic foot infectionAnimal or human bite woundsFresh water or seawater exposed woundsPeriorbital or orbital cellulitisSurgical site infection or pyomyositis
Applicable Regions
USEUAU
AU: IV and oral beta-lactam doses follow the Safer Care Victoria Adult Sepsis Pathway (2025, skin source; adapted from Therapeutic Guidelines) and eTG-based durations (Aust Prescr 2019). Community MRSA is common in the NT and remote north Queensland. Doxycycline is TGA pregnancy category D; sulfamethoxazole C; clindamycin and cefalexin A.
US: IDSA 2014 alternatives: cefazolin 1 g IV 8-hourly, ceftriaxone, dicloxacillin 500 mg orally 6-hourly. Severe non-purulent infection: vancomycin plus piperacillin-tazobactam.
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the Cellulitis & Skin/Soft Tissue Infection Management (IDSA 2014)?
The Cellulitis & Skin/Soft Tissue Infection Management (IDSA 2014) is a management clinical algorithm for Infectious Disease. It provides a structured decision tree to guide clinical decision-making, based on IDSA Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update (Stevens DL et al., Clin Infect Dis 2014;59:e10-e52).
What guideline is the Cellulitis & Skin/Soft Tissue Infection Management (IDSA 2014) based on?
This algorithm is based on IDSA Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update (Stevens DL et al., Clin Infect Dis 2014;59:e10-e52) (DOI: 10.1093/cid/ciu296).
What are the limitations of the Cellulitis & Skin/Soft Tissue Infection Management (IDSA 2014)?
Known limitations include: Adults only. Children need weight-based doses from a paediatric guideline.; MRSA rates differ by region. Use local susceptibility data (Australia: Therapeutic Guidelines: Antibiotic).; Bites, water-exposed wounds, diabetic foot, orbital cellulitis and neutropenia need specific pathways.; Doses assume normal renal function; adjust vancomycin and TMP-SMX in renal impairment.; Surgical site infections and pyomyositis are not covered; use a specific guideline.. Individual patient factors may require deviation from these recommendations.
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