Paeds · paediatric-dermatology
Impetigo and bacterial skin infection
Also known as Impetigo · School sores · Non-bullous impetigo · Bullous impetigo · Staphylococcal scalded skin syndrome · Community-acquired MRSA skin and soft tissue infection
Fellowship topic on impetigo and bacterial skin infection in children: the non-bullous and bullous forms of impetigo, ecthyma, and the toxin-mediated staphylococcal scalded skin syndrome; the Staphylococcus aureus and group A streptococcal pathophysiology including desmoglein-cleaving exfoliative toxins; the differential of crusted and blistering paediatric rashes; a clinical diagnosis with swabs reserved for atypical or recurrent disease; stepwise topical and oral antibiotic treatment matched to extent and region, with incision-and-drainage-centred management of abscess and community-acquired MRSA; the post-streptococcal glomerulonephritis complication and the skin-strep-versus-throat-strep distinction from rheumatic fever; and ANZ, UK, US and Canada guidance including remote Indigenous endemic disease.
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Target exams
Red flags
- A febrile, irritable infant with widespread tender erythema and flaccid bullae or sheet-like peeling — staphylococcal scalded skin syndrome; admit for IV anti-staphylococcal therapy, fluid and wound care
- A rapidly spreading, painful, indurated plaque with systemic upset, bullae, crepitus or sepsis — cellulitis, necrotising fasciitis or toxin-mediated escalation; treat as an emergency
- An immunocompromised, poorly controlled atopic-dermatitis or malnourished child with extensive or recurrent impetigo — high risk of dissemination and colonisation failure
- Haematuria, oedema or hypertension one to three weeks after a skin infection — post-streptococcal glomerulonephritis; check blood pressure and urinalysis
- Recurrent furunculosis or abscess in the household — consider community-acquired MRSA and a decolonisation strategy rather than repeated antibiotics alone
Life stages
Care settings
Clinical exam formats
Board mappings
- General Paediatrics and Dermatology: impetigo — recognition of non-bullous and bullous forms, topical and oral treatment, complications
- Infectious diseases: staphylococcal and streptococcal skin infection, community-acquired MRSA, staphylococcal scalded skin syndrome
- Renewed curriculum — Infectious diseases and population child health: endemic impetigo in remote communities, public-health and decolonisation strategy
- Dermatology: blistering disorders of infancy and toxin-mediated staphylococcal disease
- General Paediatrics: diagnosis and stepwise antibiotic treatment of impetigo and the recognising of the sick child with toxin-mediated disease
- Public health: household transmission, school exclusion and recurrent disease
- Long Case / Structured discussion: a child with recurrent or extensive impetigo — cause, treatment, complications and public health
- Communication station: explaining topical versus oral therapy, school exclusion and the prevention of post-streptococcal complications
- Level 2 / 3 — Infection and Dermatology: bacterial skin infection, toxin-mediated staphylococcal disease and antibiotic stewardship
- Public health and health improvement: transmission control in schools and remote communities
- Foundation of Practice (FOP): impetigo clinical forms, complications and the distinction from other blistering rashes
- Applied Knowledge in Practice (AKP): antibiotic choice by extent and region, MRSA, staphylococcal scalded skin syndrome
- History-taking and management: the child with crusted or blistering skin lesions and recurrent skin sepsis
- Communication: explaining treatment, school exclusion and household measures to a family
- General Pediatrics Content Outline — impetigo and bacterial skin infections: diagnosis, treatment and complications
- Infectious Diseases: Staphylococcus aureus and group A streptococcal skin infection, CA-MRSA, incision and drainage
- Dermatology: staphylococcal scalded skin syndrome and blistering disorders
- Patient Care: diagnosis and stepwise, stewardship-conscious management of bacterial skin infection across severity
- Systems-Based Practice and Population Health: school exclusion, household decolonisation and endemic-disease strategy
- Medical Knowledge: toxin pathophysiology, post-streptococcal complications and antibiotic selection
- Medical Expert: impetigo and bacterial skin infection diagnosis, treatment and complications
- Health Advocate and Collaborator: school and household transmission control, remote-community and Indigenous health
- Communicator: explaining treatment, exclusion and prevention to families
Two lesions, two mechanisms
Non-bullous impetigo
Bullous impetigo
Exfoliative toxins A and B from Staphylococcus aureus cleave desmoglein-1, the adhesion molecule that glues the top layer of the epidermis together at the granular layer. Same target, same split, two diseases: the toxin acting locally at the lesion gives bullous impetigo; the same toxin circulating systemically in an infant gives staphylococcal scalded skin syndrome. Remember the mucosae are spared in both, because desmoglein-3 compensates across the wet surfaces. [8]
Overview & Definition
Picture a four-year-old brought to the clinic with a crusted, weeping sore under the nose that started as a small spot three days ago, has spread across the cheek, and now crops up on the sibling's chin. The child is otherwise well, afebrile and scratching. This is the everyday face of bacterial skin infection in childhood — common, contagious, eminently treatable, and quietly capable, in its complications, of causing real harm. Recognising the form, choosing the treatment by extent, and watching for the post-streptococcal sequelae is the whole skill. [2] [1]
Impetigo is a superficial, highly contagious bacterial infection of the epidermis caused most often by Staphylococcus aureus and group A beta-haemolytic streptococcus (Streptococcus pyogenes). It spreads by direct contact and through broken skin — an insect bite, an abrasion, or the cracked skin of atopic dermatitis giving the organism its entry. It is the most common bacterial skin infection in children worldwide, and its burden falls heavily on young children in warm, humid climates and in disadvantaged and remote communities. [2] [9]
The clinician's task has three layers. The first is recognition — distinguishing impetigo from its mimics, and the benign superficial form from the toxin-mediated and invasive diseases that need the hospital. The second is treatment matched to extent, organism and region, delivered with antibiotic-stewardship discipline so that the common disease does not drive resistance. The third is the public-health and complication layer: school exclusion, household decolonisation, and the vigilance for post-streptococcal glomerulonephritis that turns a skin sore into a renal problem weeks later. [1] [2]
References12ShowHide
- [1]Koning S; van der Sande R; Verhagen AP; van Suijlekom-Smit LW; et al Interventions for impetigo. Cochrane Database Syst Rev, 2012.PMID 22258953
- [2]Bowen AC; Mahe A; Hay RJ; Andrews RM; et al The Global Epidemiology of Impetigo: A Systematic Review of the Population Prevalence of Impetigo and Pyoderma. PLoS One, 2015.PMID 26317533
- [3]Bowen AC; Tong SY; Andrews RM; O'Meara IM; et al Short-course oral co-trimoxazole versus intramuscular benzathine benzylpenicillin for impetigo in a highly endemic region: an open-label, randomised, controlled, non-inferiority trial. Lancet, 2014.PMID 25172376
- [4]Stevens DL; Bisno AL; Chambers HF; Dellinger EP; et al Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis, 2014.PMID 24973422
- [5]Miller LG; Daum RS; Creech CB; Young D; et al Clindamycin versus trimethoprim-sulfamethoxazole for uncomplicated skin infections. N Engl J Med, 2015.PMID 25785967
- [6]Talan DA; Mower WR; Krishnadasan A; Abrahamian FM; et al Trimethoprim-Sulfamethoxazole versus Placebo for Uncomplicated Skin Abscess. N Engl J Med, 2016.PMID 26962903
- [7]Kaplan SL; Forbes A; Hammerman WA; Lamberth L; et al Randomized trial of bleach baths plus routine hygienic measures vs. routine hygienic measures alone for prevention of recurrent infections. Clin Infect Dis, 2014.PMID 24265356
- [8]Gray L; Hansen AM; Cipriano SD Pediatric Staphylococcal Scalded Skin Syndrome: A Systematic Review of the Literature to Inform Work-Up and Management. Pediatr Dermatol, 2025.PMID 40650480
- [9]Gahlawat G; Tesfaye W; Bushell M; Abrha S; et al Emerging Treatment Strategies for Impetigo in Endemic and Nonendemic Settings: A Systematic Review. Clin Ther, 2021.PMID 34053699
- [10]Hyun DY; Mason EO; Forbes A; Kaplan SL Trimethoprim-sulfamethoxazole or clindamycin for treatment of community-acquired methicillin-resistant Staphylococcus aureus skin and soft tissue infections. Pediatr Infect Dis J, 2009.PMID 19057459
- [11]Moran GJ; Krishnadasan A; Mower WR; Abrahamian FM; et al Effect of Cephalexin Plus Trimethoprim-Sulfamethoxazole vs Cephalexin Alone on Clinical Cure of Uncomplicated Cellulitis: A Randomized Clinical Trial. JAMA, 2017.PMID 28535235
- [12]Daum RS; Miller LG; Immergluck L; Fritz S; et al A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses. N Engl J Med, 2017.PMID 28657870