ImpetigoMANAGEMENT

INFECTIOUS DISEASE PRESENTATIONS · 12 SECTIONS

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474 items

☷ Legend

01Approach to the Critical Patient/attcp45

Triage and escalation

›Escalation triggers

›If fever with hypotension, activate sepsis pathway

›MAP < 65 mmHg after initial fluids

›Lactate >= 2 mmol/l

›If rapidly progressive pain out of proportion, necrotizing soft tissue infection pathway

›Crepitus

›Skin anesthesia

›If diffuse erythema with skin tenderness and systemic toxicity, staphylococcal scalded skin syndrome pathway

›Periorificial crusting

›Positive Nikolsky sign

›If orbital symptoms with periocular involvement, orbital cellulitis pathway

›Pain with extraocular movements

›Proptosis

›Immediate stabilization

›If shock, initiate fluid resuscitation and vasopressor per protocol

›Balanced crystalloids

›Norepinephrine first-line for persistent hypotension

›If airway threat from facial soft tissue swelling, early airway planning

›Anesthesia support

›ENT support

Key concepts

›Impetigo essentials

›Superficial epidermal bacterial infection

›Nonbullous form most common

›Bullous form due to toxin-producing Staphylococcus aureus

›Primary impetigo on intact skin

›Minor trauma

›Insect bites

›Secondary impetigo over dermatoses

›Eczema

›Scabies

›Coding and standardization

›ICD-10

›L01.00 impetigo unspecified

›L01.01 nonbullous impetigo

›L01.03 bullous impetigo

›SNOMED CT concepts

›Impetigo disorder

›Bullous impetigo disorder

Infection control

›Transmission reduction

›Contact precautions for weeping lesions in clinical setting

›Gloves and gown for direct contact

›Hand hygiene before and after contact

›School and daycare exclusion guidance planning

›Exclusion until 24 hours after starting effective antibiotics

›Cover lesions when feasible

02History/hx57

Presenting features

›Symptom pattern

›Honey-colored crusted erosions

›Often around nares and mouth

›Mild pruritus common

›Vesicles or pustules preceding crusts

›Lesions at different stages

›Minimal pain typical

›Bullae with thin roof and collarette of scale

›Rupture leaving shallow erosions

›Regional outbreaks in children

›Time course

›Onset and progression

›New lesions over days

›Failure of simple hygiene measures

›Prior similar episodes

›Recurrent impetigo

›Household clustering

Exposures and risks

›Epidemiologic risks

›Close contact environments

›Daycare or school

›Contact sports

›Household contacts with skin infection

›Shared towels or bedding

›Shared razors

›Host risks

›Atopic dermatitis

›Excoriations

›Barrier dysfunction

›Scabies exposure

›Nocturnal pruritus in household

›New rash in contacts

›Diabetes mellitus

›Poor wound healing

›Higher complication risk

›Immunocompromise

›Systemic steroids

›HIV

›Community MRSA risk factors

›Prior MRSA infection or colonization

›Recent incarceration or shelter living

Red flags and complications history

›Systemic symptoms

›Fever

›Concern for invasive infection

›Alternative diagnosis consideration

›Malaise

›Staphylococcal toxin syndromes

›Bacteremia concern in high-risk hosts

›Complication clues

›Dark urine or edema after skin infection

›Post-streptococcal glomerulonephritis concern

›Recent sore throat not required

›Severe pain, rapidly spreading erythema, skin discoloration

›Necrotizing infection concern

›Urgent escalation

›Periorbital swelling or vision symptoms

›Periorbital or orbital cellulitis concern

›Urgent escalation

03Physical Exam/exam41

Skin findings

›Lesion morphology

›Nonbullous pattern

›Erythematous papules evolving to vesicles or pustules

›Honey-colored crusts on erosions

›Bullous pattern

›Flaccid bullae with clear or yellow fluid

›Collarette of scale after rupture

›Ecthyma features

›Punched-out ulcer with adherent crust

›Induration extending into dermis

›Distribution

›Face

›Perinasal and perioral predominance

›Angular cheilitis involvement

›Extremities

›Exposed areas

›Sites of trauma or insect bites

Severity and systemic assessment

›Vital signs

›Fever

›Consider deeper infection or alternative diagnosis

›Threshold-based escalation per local sepsis protocol

›Tachycardia

›Pain vs infection severity

›Dehydration consideration in children

›Regional findings

›Lymphadenopathy

›Tender regional nodes

›Lymphangitic streaking

›Cellulitis extension

›Diffuse warmth and edema beyond crusts

›Rapid progression concern

PITFALLS

›Misclassification risks

›HSV labialis mistaken for impetigo

›Grouped vesicles

›Burning or pain prodrome

›Allergic contact dermatitis mistaken for impetigo

›Linear or geometric pattern

›Clear exposure trigger

›Scabies with secondary impetiginization

›Burrows

›Interdigital involvement

04Differential Diagnosis/ddx37

Infectious mimics

›Bacterial and toxin syndromes

›Ecthyma

›Deeper ulcerative lesions

›Higher scarring risk

›Periorificial dermatitis with secondary infection

›Papulopustular eruption

›Irritant triggers

›Staphylococcal scalded skin syndrome

›Diffuse erythema and tenderness

›Superficial desquamation

›Viral and fungal

›Herpes simplex

›Grouped vesicles on erythematous base

›Painful lesions

›Varicella or zoster

›Dermatomal distribution for zoster

›Lesions in multiple stages for varicella

›Tinea faciei

›Annular plaques with scale

›Central clearing

Inflammatory and other

›Dermatitis and infestations

›Atopic dermatitis flare

›Lichenification

›Flexural predominance

›Allergic contact dermatitis

›Pruritic erythematous plaques

›Vesiculation in exposure pattern

›Scabies

›Burrows

›Nocturnal pruritus

›Autoimmune blistering

›Bullous pemphigoid

›Tense bullae

›Older adult predominance

›Pemphigus vulgaris

›Painful erosions

›Mucosal involvement

05Laboratory Tests/lt18

When labs are needed

›Lab indications

›Systemic toxicity

›CBC for leukocytosis trend

›Lactate for sepsis risk stratification

›Suspected renal complication

›Creatinine and electrolytes

›Urinalysis for hematuria and proteinuria

›Immunocompromised host with extensive disease

›CBC for neutropenia

›Blood cultures if febrile

Microbiology

›Pathogen identification strategy

›Lesion culture and susceptibility

›Recurrent impetigo

›Treatment failure after 48 to 72 hours

›Community outbreak investigation

›MRSA colonization consideration

›Prior MRSA history

›High local prevalence settings

06Diagnostic Tests/dt37

Scoring Systems

›Clinical decision tools

›No validated impetigo severity score in routine ED use

›Severity based on lesion count and distribution

›Systemic symptoms as escalation criterion

›Treatment selection framework

›Limited localized lesions

›Topical antibiotic preferred

›Add hygiene and lesion coverage

›Multiple lesions or outbreaks

›Oral antibiotic consideration

›Culture if recurrent or failure

MRI

›MRI role

›Not routine for uncomplicated impetigo

›Superficial epidermal process

›Clinical diagnosis typical

›Deep infection evaluation when concern exists

›Osteomyelitis concern under chronic ulceration

›Necrotizing infection differentiation support

›CT role

›Not routine for uncomplicated impetigo

›No expected deep tissue involvement

›Avoid radiation in children when low value

›Complication evaluation

›Orbital cellulitis concern with periocular involvement

›CT orbits with contrast per local pathway

›Urgent specialty consultation

Ultrasound (or US)

›Ultrasound role

›Not routine for typical impetigo

›No abscess expected in superficial crusted lesions

›Clinical diagnosis sufficient

›POCUS for abscess vs cellulitis when fluctuance or induration

›Subcutaneous fluid collection

›Incision and drainage pathway if present

›Antibiotics adjunct decision based on severity

›Cobblestoning without collection

›Cellulitis management pathway

›Oral antibiotic selection per local resistance

07Disposition/dispo30

Outpatient vs admission

›Outpatient criteria

›No systemic toxicity

›Afebrile or low-grade fever without instability

›Normal perfusion and mentation

›Limited disease burden

›Localized lesions

›No rapidly progressive cellulitis

›Reliable follow-up and hygiene capacity

›Caregiver able to perform skin care in children

›Ability to obtain medications

›Admission or transfer criteria

›Systemic illness

›Sepsis physiology

›Dehydration requiring IV fluids

›Extensive skin involvement

›Concern for toxin-mediated disease

›Failure of outpatient therapy with progression

›High-risk host

›Significant immunocompromise

›Inability to maintain wound care

›Complications

›Periorbital or orbital cellulitis concern

›Necrotizing infection concern

Follow-up

›Reassessment planning

›Clinical improvement expectation

›Less drainage and crusting by 48 to 72 hours

›No new lesions after therapy initiation

›Follow-up options

›Primary care within 2 to 3 days if not improving

›Dermatology for recurrent or atypical presentations

08Treatment/t94

General measures

›Skin care and transmission control

›Gentle cleansing

›Warm water soaks to soften crusts

›Mild soap cleansing once or twice daily

›Lesion management

›Keep nails short

›Cover lesions with nonadherent dressing when feasible

›Household measures

›Avoid sharing towels, bedding, cosmetics

›Launder clothing and linens in hot water when possible

Topical antibiotics

›Localized impetigo regimen

›Mupirocin 2% ointment

›Apply thin layer three times daily for 5 days

›Extend to 7 days if slow response

›Avoid use if known mupirocin resistance locally high

›Perinasal colonization use in recurrent disease

›Intranasal application twice daily for 5 days

›Combine with chlorhexidine washes for decolonization plan

›Retapamulin 1% ointment

›Apply twice daily for 5 days

›Use for nonbullous impetigo

›Not for mucosal surfaces

›Age limits per local formulary

›Avoid in very young infants if restricted

›Confirm availability and coverage

›Ozenoxacin 1% cream

›Apply twice daily for 5 days

›Option when available

›Consider for localized lesions

Oral antibiotics

›Indications for oral therapy

›Numerous lesions

›Widespread distribution

›Multiple body sites

›Bullous impetigo

›Higher likelihood of S aureus

›Outbreak control consideration

›Topical failure

›No improvement by 48 to 72 hours

›New lesions despite adherence

›MSSA and Streptococcus coverage options

›Cephalexin

›Adult dosing

›500 mg PO four times daily for 5 to 7 days

›Renal dosing adjustment when eGFR reduced

›Pediatric dosing

›25 to 50 mg/kg/day PO divided every 6 to 8 hours for 5 to 7 days

›Maximum 4 g/day

›Dicloxacillin

›Adult dosing

›500 mg PO four times daily for 5 to 7 days

›Take on empty stomach if tolerated

›Pediatric dosing

›25 to 50 mg/kg/day PO divided every 6 hours for 5 to 7 days

›Maximum per local pediatric limits

›MRSA risk options

›Clindamycin

›Adult dosing

›300 to 450 mg PO three times daily for 5 to 7 days

›Monitor for antibiotic-associated diarrhea

›Pediatric dosing

›20 to 40 mg/kg/day PO divided every 6 to 8 hours for 5 to 7 days

›Maximum per local pediatric limits

›Trimethoprim-sulfamethoxazole

›Adult dosing

›1 to 2 double-strength tablets PO twice daily for 5 to 7 days

›Limited streptococcal coverage consideration

›Pediatric dosing

›8 to 12 mg/kg/day trimethoprim component PO divided every 12 hours for 5 to 7 days

›Avoid in infants under 2 months

›Doxycycline

›Adult dosing

›100 mg PO twice daily for 5 to 7 days

›Limited streptococcal coverage consideration

›Pediatric constraints

›Avoid under age 8 years unless specialist-directed

›Photosensitivity counseling

›Evidence and guideline framing

›Class I recommendation for antibiotics in confirmed impetigo based on expert consensus

›Topical preferred for limited lesions

›Oral preferred for extensive disease

›ACEP Level C alignment for uncomplicated skin infection antibiotic selection based on local resistance

›Culture-driven adjustment for failure or outbreaks

›MRSA coverage when epidemiologic risk high

Decolonization and recurrence

›Recurrent impetigo strategy

›Household cluster management

›Treat symptomatic contacts

›Emphasize hygiene and laundry measures

›Decolonization regimen consideration

›Intranasal mupirocin twice daily for 5 days

›Repeat only with clinician direction

›Resistance risk with frequent use

›Chlorhexidine washes daily for 5 days

›Avoid eyes and ears

›Alternative dilute bleach baths per specialist plan

09Special Populations/sp31

Pregnancy

›Pregnancy considerations

›Preferred agents

›Topical mupirocin for localized disease

›Cephalexin for extensive disease

›Agents to avoid or use with caution

›Doxycycline avoidance

›Trimethoprim-sulfamethoxazole avoidance near term when possible

›Lactation considerations

›Avoid infant direct contact with treated area until absorbed

›Avoid application on nipple area unless directed

Geriatric

›Older adult considerations

›Atypical presentations

›Bullous lesions mistaken for autoimmune blistering disease

›Higher risk of ecthyma with vascular disease

›Medication safety

›Renal dosing adjustment for cephalexin and trimethoprim-sulfamethoxazole

›Drug interaction review for trimethoprim-sulfamethoxazole with warfarin

›Skin integrity optimization

›Emollients for xerosis reduction

›Avoid adhesive trauma from dressings

Pediatrics

›Pediatric essentials

›First-line for limited lesions

›Topical antibiotic for 5 days

›Daycare and school exclusion planning

›Oral therapy triggers

›Numerous lesions

›Bullous impetigo

›Household outbreak dynamics

›Weight-based dosing safety

›Use mg/kg/day dosing with maximum limits

›Caregiver education for adherence and hygiene

10Background/b30

Epidemiology

›Population patterns

›Common in children age 2 to 5 years

›Daycare and school transmission

›Summer and humid climate association

›Risk increased with skin barrier disruption

›Atopic dermatitis

›Insect bites

›Common organisms

›Staphylococcus aureus

›Group A Streptococcus

Pathophysiology

›Mechanisms

›Nonbullous impetigo

›Superficial infection of epidermis

›Vesiculopustules rupture to crusts

›Bullous impetigo

›Exfoliative toxin production by S aureus

›Intraepidermal split leading to flaccid bullae

›Complication pathways

›Post-streptococcal glomerulonephritis after streptococcal strains

›Bacteremia rare but possible in high-risk hosts

Therapeutic Considerations

›Treatment rationale

›Antibiotics shorten course and reduce transmission

›Faster lesion resolution than hygiene alone

›Reduced household spread

›Topical vs oral decision

›Topical for limited disease to reduce systemic adverse effects

›Oral for extensive disease or bullous disease

›Resistance considerations

›MRSA prevalence variability by region

›Mupirocin resistance risk with frequent decolonization

11Patient Discharge Instructions/pdi22

copy discharge instructions

›Impetigo discharge instructions

›Medication use

›Use antibiotics exactly as prescribed

›If topical, apply thin layer to lesions after gentle cleansing

›Skin care

›Wash hands before and after touching the area

›Keep nails short and avoid scratching

›Cover lesions with a clean nonstick dressing when possible

›Prevent spread

›Do not share towels, bedding, makeup, razors

›Wash clothing, towels, and bedding regularly

›Stay home from school or daycare until 24 hours after starting antibiotics

›Expected improvement

›Fewer new lesions within 1 to 2 days

›Less crusting and drainage within 2 to 3 days

›Return to ED now

›Fever with worsening skin redness or swelling

›Rapidly spreading redness or severe pain

›Red streaks moving up the limb

›Swelling around the eye, eye pain, vision changes

›Vomiting, lethargy, signs of dehydration

›No improvement after 48 to 72 hours of antibiotics

12References/r32

Clinical guidelines and evidence sources

›Core references

›Infectious Diseases Society of America skin and soft tissue infection guideline

›Impetigo management recommendations

›Culture and MRSA coverage considerations

›American Academy of Pediatrics Red Book

›Pediatric impetigo therapy and dosing guidance

›School exclusion guidance

›NICE antimicrobial prescribing guidance for impetigo

›Topical vs oral selection framework

›Antimicrobial stewardship emphasis

›CDC community MRSA clinical resources

›Risk factor framing

›Hygiene and decolonization considerations

›Evidence level conventions

›ACEP Level A definition

›High-quality evidence with consistent results

›Rarely available for superficial SSTI treatment comparisons

›ACEP Level B definition

›Moderate evidence supporting common practice

›Applies to selected SSTI antibiotic strategies by local resistance

›ACEP Level C definition

›Consensus and expert opinion

›Applies to many impetigo operational decisions in ED settings

›Class I definition

›Benefit much greater than risk

›Antibiotic therapy for confirmed impetigo in most patients

›Class IIa definition

›Benefit greater than risk

›Culture in recurrent or outbreak settings

›Class IIb definition

›Benefit at least equal to risk

›Decolonization regimens for recurrent disease in select households

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Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

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