Infection
How NZ, Australian, and NICE guidelines compare across cellulitis, impetigo, abscess, and bite wounds. First-line agents are broadly consistent; the notable divergences are around impetigo topical therapy and empirical MRSA cover.
Scope: common primary care SSTIs in immunocompetent adults and children. Excludes necrotising fasciitis (emergency referral), diabetic foot infections, and hospital-acquired infections.
Where they agree
Where they diverge
Comparison
| Domain | NZ - BPAC 2022 | AU - Therapeutic Guidelines | International - NICE NG141 / NG153 |
|---|---|---|---|
| Classification | Divided into non-purulent (cellulitis, erysipelas) and purulent (abscess, furuncle, infected wound) presentations. Impetigo treated separately. Severity stratification guides admission vs oral vs topical management. | Similar framework. Therapeutic Guidelines distinguishes cellulitis, erysipelas, folliculitis/furunculosis, and wound infections with specific antibiotic recommendations for each. Eron classification (I-IV) referenced for cellulitis severity. | NICE has separate guidelines for cellulitis and erysipelas (NG141) and impetigo (NG153). NG141 distinguishes erysipelas (superficial, demarcated, typically streptococcal) from cellulitis (deeper, less defined) more explicitly than NZ or AU primary care guidance. |
| Cellulitis / erysipelas - first-line antibiotic |
Cefalexin 500mg four times daily for 5 daysFunded OR flucloxacillin 500mg four times daily for 5 daysFunded Review at 48 hours. Extend to 7 days if slow response. If penicillin allergy: erythromycin or doxycycline. |
Cefalexin 500mg four times daily for 5 daysPBS OR dicloxacillin 500mg four times daily for 5 daysPBS Dicloxacillin preferred where flucloxacillin not available. Review at 48-72 hours. |
NICE NG141: flucloxacillin 500mg-1g four times daily for 5-7 days (first-line) Erysipelas (typically streptococcal): phenoxymethylpenicillin (penicillin V) 500mg four times daily is reasonable for uncomplicated cases. Review at 24-48 hours. If penicillin allergy: clarithromycin or doxycycline. |
| Purulent infections (abscess, furuncle) |
Incision and drainage is the definitive treatment for fluctuant abscess.First-line Antibiotics after I&D usually not required for small, uncomplicated abscess in immunocompetent patients. Add cefalexin or flucloxacillin if there is surrounding cellulitis >2cm or systemic features. Warm compress for non-fluctuant furuncles; incise when pointing. |
I&D is the primary intervention. Post-I&D antibiotics generally not required for simple abscess. Therapeutic Guidelines recommend antibiotics if: abscess >2cm, multiple lesions, significant surrounding cellulitis, fever, or immunocompromise. Cefalexin or dicloxacillin if treating. | NICE: I&D is the first-line treatment. Most small abscesses do not require antibiotics after drainage. Consider antibiotics (flucloxacillin) if surrounding cellulitis, systemic features, or immunosuppression. Sending wound swab at time of I&D is recommended to guide therapy if response is poor. |
| Impetigo - topical treatment |
Mupirocin 2% ointment three times daily for 5-7 daysFunded Hydrogen peroxide cream (Crystacide) is an option but PHARMAC funding status should be confirmed at time of prescribing.Check PHARMAC Suitable for limited, non-bullous impetigo. Cover lesions loosely; advise on hygiene and non-sharing of towels. |
Mupirocin 2% ointment three times daily for 5 daysPBS Therapeutic Guidelines note that mupirocin resistance is emerging among Staphylococcal isolates. Hydrogen peroxide 1% cream available as an alternative for non-MRSA settings. |
NICE NG153 (2020): hydrogen peroxide 1% cream three times daily for 5 days is now first-line for non-bullous impetigo in people not at high risk. Mupirocin is explicitly de-prioritised in NICE guidance to preserve mupirocin efficacy for MRSA decolonisation. This represents a significant departure from prior practice and from NZ/AU current recommendations. |
| Impetigo - oral treatment |
Indicated for: widespread or bullous impetigo, failure of topical therapy, or systemic features. Flucloxacillin 250-500mg four times daily for 5 daysFunded OR cefalexin 250-500mg four times daily for 5 daysFunded In NZ, treat any impetigo in Maori or Pacific children promptly given Group A Streptococcal skin infection as a risk factor for acute rheumatic fever. |
Cefalexin or dicloxacillin for 5 days.PBS Bullous impetigo is typically staphylococcal and requires oral therapy from the outset. Non-bullous impetigo may be streptococcal; cefalexin covers both organisms. |
NICE NG153: flucloxacillin 250-500mg four times daily for 5 days if oral therapy required. If penicillin allergy: clarithromycin. NICE also advises that widespread impetigo or failure of topical therapy should trigger oral treatment rather than a switch to a different topical agent. |
| MRSA - empirical oral cover |
Community-acquired MRSA (CA-MRSA) prevalence in NZ is lower than in Australia, particularly outside specific risk populations. Consider empirical CA-MRSA cover if: Treatment failure after 48-72h of standard therapy, recurrent skin infections, known CA-MRSA contact, or patient from a high-risk setting (corrections facility, certain Pacific communities). Trimethoprim 300mg once dailyFunded OR doxycycline 100mg twice dailyFunded Swab wound or abscess fluid and tailor to sensitivities when available. |
CA-MRSA prevalence is significantly higher in Australia, especially in remote communities and among Indigenous Australians. Therapeutic Guidelines recommend a lower threshold for empirical CA-MRSA cover in these settings. Cotrimoxazole (trimethoprim/sulfamethoxazole) 160/800mg twice dailyPBS OR doxycycline 100mg twice dailyPBS Wound swab is strongly encouraged before starting. |
NICE NG141 does not recommend routine empirical CA-MRSA cover for cellulitis in the UK primary care context. If MRSA is suspected or confirmed: doxycycline or trimethoprim. NICE emphasises sending wound swabs or tissue samples to guide therapy in any patient not responding to standard treatment. Do not start MRSA-active antibiotics empirically without clinical justification. |
| Bite wounds (dog, cat, human) |
Irrigate copiously and debride. Wound closure depends on location and time since injury. Prophylactic or therapeutic antibiotics: co-amoxiclav (amoxicillin/clavulanate) 500/125mg three times daily for 5 daysFunded Human bites carry higher infection risk. Assess tetanus and blood-borne virus exposure. Do not give cephalosporin alone for cat bites - Pasteurella multocida is resistant. |
Co-amoxiclav 875/125mg twice daily for 5 daysPBS Therapeutic Guidelines recommend prophylaxis for all cat bites, puncture wounds, hand bites, and bites in immunocompromised patients. Dog bites in low-risk locations with low-depth wounds may not require prophylaxis. If penicillin allergic: seek specialist advice - no single agent covers the full polymicrobial range of bite pathogens reliably. |
NICE: co-amoxiclav (amoxicillin/clavulanate) for 5 days. Offer prophylaxis for all cat bites and human bites, and for dog bites to the face, hand, foot, or genitalia, or where there is devitalised tissue. Clarithromycin plus metronidazole if penicillin allergic. NICE emphasises that the bite site should be irrigated thoroughly before any other intervention. |
| Duration of treatment and review |
Cellulitis: 5 days minimum; extend to 7-10 days if slow response. Arrange clinical review at 48 hours, especially for lower limb cellulitis. Mark the advancing margin of erythema with a skin pen at presentation to allow objective assessment of progression vs response. Impetigo: 5-7 days topical or oral. Exclude from school or early childhood education until lesions have crusted or 24h of antibiotic therapy has been completed. |
Cellulitis: 5-7 days, review at 48-72 hours. Therapeutic Guidelines advise longer courses (10-14 days) for severe or slow-responding cellulitis. Bilateral lower limb swelling is often not cellulitis - consider oedema, lipodermatosclerosis, or DVT as alternative diagnoses. | NICE NG141: 5-7 days; review at 24-48 hours and again at 5 days if not improving. Extend course if ongoing signs of infection. NICE also recommends considering compression bandaging for lower limb cellulitis to reduce swelling and support recovery. Prescribe the full course and advise patients not to stop early if improving. |
| Criteria for hospital admission | Admit if any of: systemic sepsis (fever, rigors, hypotension, tachycardia), rapidly spreading cellulitis, failure to respond after 48h oral antibiotics, periorbital or facial cellulitis (admit directly, ophthalmology review if periorbital), bullous cellulitis or features suggesting necrotising fasciitis, immunocompromise, or significant comorbidity preventing adequate oral therapy. | Similar criteria. Therapeutic Guidelines add: elderly patients with large areas of involvement, infection involving the foot or lower limb in patients with peripheral vascular disease or diabetes, and any patient in whom compliance with oral antibiotics is uncertain. | NICE NG141: use an early warning score (eg NEWS2) to guide urgency. Immediate referral if: rapidly spreading, systemic toxicity, very young children, patients who are immunocompromised or have significant comorbidities. Offer same-day specialist assessment for periorbital cellulitis regardless of systemic severity. |
| Predisposing factors and prevention | Identify and treat tinea pedis as the most common portal of entry for lower limb cellulitis. Treat with topical antifungal (clotrimazole, econazole - funded) for 4 weeks. Address skin breaks, venous insufficiency (compression stockings), lymphoedema (complex decongestive therapy referral), and obesity. For recurrent cellulitis (≥3 episodes), consider prophylactic penicillin V 250mg twice daily for 6-12 months. | Similar approach. Therapeutic Guidelines specifically recommend treating tinea pedis in all patients with lower limb cellulitis, whether or not tinea is clinically evident at presentation, given its high prevalence as a subclinical risk factor. | NICE NG141: explicitly recommends addressing predisposing factors as part of cellulitis management. For recurrent cellulitis: offer low-dose prophylactic penicillin V for 6 months; review at 6 months and continue if recurrence risk persists. Advise on skin moisturisation to maintain barrier function in patients with dry or eczematous skin. |
NZ clinical context
PHARMAC funding and population-specific considerations
All first-line agents for SSTIs are funded in NZ without access restrictions:
This is the most important NZ-specific consideration for SSTIs, and it is not reflected in NICE or Therapeutic Guidelines in the same way. New Zealand has some of the highest rates of acute rheumatic fever (ARF) in the developed world, overwhelmingly concentrated in Maori and Pacific children aged 5-14 years.7
Group A Streptococcal (GAS) skin infection is a well-established trigger for ARF in these populations, in addition to GAS pharyngitis. In high-prevalence regions (Auckland, Northland, Counties Manukau, Gisborne, Hawke's Bay), any GAS-infected skin lesion in a Maori or Pacific child should be treated promptly and completely. This shifts the risk-benefit calculation for impetigo treatment: what might be a "wait and see" or topical-only decision in a low-risk child becomes more clearly an indication for oral antibiotics in a high-risk child. Cefalexin covers both Staphylococcus aureus and Group A Streptococcus, making it the practical first choice.
Community-acquired MRSA prevalence in New Zealand is substantially lower than in Australia, particularly relative to remote and rural Australian communities where CA-MRSA rates among Indigenous populations can be very high. In NZ, CA-MRSA is most likely in:
Do not routinely apply the Australian threshold for empirical CA-MRSA cover to NZ patients. When CA-MRSA is suspected, send a swab and use trimethoprim 300mg once daily or doxycycline 100mg twice daily while awaiting sensitivities.
True bilateral cellulitis is rare. Both lower legs are almost never simultaneously infected. A patient presenting with bilateral redness, swelling, and warmth in the lower limbs almost certainly has an alternative diagnosis: lipodermatosclerosis, bilateral chronic venous insufficiency, dependent oedema (cardiac, hepatic, or nutritional), or contact dermatitis. Prescribing antibiotics for bilateral "cellulitis" is a common and avoidable error. Look for the asymmetry, the portal of entry, the tenderness pattern, and the systemic features that distinguish genuine cellulitis from venous or inflammatory causes.
Up to 70-80% of recurrent lower limb cellulitis is associated with tinea pedis.1 Treat tinea pedis in every patient with lower limb cellulitis, whether or not it is clinically obvious. Clotrimazole and econazole topical antifungals are funded. A 4-week course is required to clear tinea; advise patients that this is part of their cellulitis treatment, not a separate issue. Failure to treat tinea is the most common reason for cellulitis recurrence in primary care.
Bottom line for NZ practice
What this means in the consulting room
Sources