Table 1. Therapeutic approach to common bacterial skin infections .

Infection	Likely pathogens	Management
Impetigo	Staphylococcus aureus Streptococcus pyogenes	Mild or localised disease: wash crusts topical mupirocin Multiple lesions or recurrent disease: cultures to guide treatment oral antibiotics (dicloxacillin/cephalexin/trimethoprim plus sulfamethoxazole) for up to 10 days intravenous antibiotics if no improvement for recurrent infection due to S. aureus consider decolonisation Advice and education of household members to reduce transmission: avoid contact with lesions wash hands regularly, particularly after touching lesions
Boils and carbuncles	S. aureus S. pyogenes	Incision and drainage most important step in management: culture and susceptibility testing for lesions antibiotics if spreading cellulitis or systemic symptoms oral dicloxacillin/cephalexin for 5 days oral clindamycin, or trimethoprim plus sulfamethoxazole for community-acquired-MRSA for 5 days
Folliculitis	S. aureus S. pyogenes Pseudomonas aeruginosa	Treatment usually supportive Warm compresses or topical mupirocin In severe infection treat as per impetigo
Cellulitis and erysipelas	S. aureus Beta-haemolytic streptococci	Examine for predisposing factors Consider unusual exposures (see Table 2) – broaden antibiotic therapy if this is the case Culture and susceptibility testing for lesions, tissue or blood Elevate limb Treat underlying predisposing skin infection e.g. tinea Mild disease: oral dicloxacillin/cephalexin/clindamycin for 5–10 days oral phenoxymethylpenicillin if culture is positive or clinical presentation of S. pyogenes Severe disease or systemic features: intravenous flucloxacillin/cephazolin/vancomycin Consider decolonisation or prophylactic antibiotics with recurrent disease
Periorbital cellulitis	S. aureus Streptococcus species Haemophilus influenzae type b (in unvaccinated patients)	Mild disease: oral dicloxacillin/cephalexin/clindamycin for 7 days If suspect H. influenzae type b infection (unvaccinated, < 5yrs old): oral amoxycillin plus clavulanate, or cefuroxime for 7 days Severe disease or systemic features: treat as orbital cellulitis
Orbital cellulitis	S. aureus Streptococcus species H. influenzae type b (in unvaccinated patients) Anaerobic bacteria	Inpatient hospital management with urgent surgical opinion Blood cultures and CT scan of orbits Intravenous antibiotics
Necrotising fasciitis	S. aureus S. pyogenes Gram negatives, Clostridium species Anaerobic bacteria	Inpatient hospital management with urgent surgical debridement Culture and susceptibility testing of tissue Broad-spectrum intravenous antibiotics including clindamycin (antitoxin effect by suppressing synthesis of bacterial endotoxins)

MRSA methicillin-resistant Staphylococcus aureus