Introduction
Impetigo is a superficial bacterial skin infection usually caused by either Staphylcoccus aureus or Streptococcus pyogenes. It can be a primary infection or a complication of an existing skin condition such as eczema (in this case), scabies or insect bites. Impetigo is common in children, particularly during warm weather.
Epidemiology
- Incidence: 250.00 cases per 100,000 person-years
- Peak incidence: 1-5 years
- Sex ratio: 1:1
| Condition | Relative incidence |
|---|---|
| Impetigo | 1 |
| Shingles | 0.72 |
| Eczema herpeticum | 0.004 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Pathophysiology
Spread is by direct contact with discharges from the scabs of an infected person. The bacteria invade skin through minor abrasions and then spread to other sites by scratching. Infection is spread mainly by the hands, but indirect spread via toys, clothing, equipment and the environment may occur. The incubation period is between 4 to 10 days.
Clinical features
The infection can develop anywhere on the body but lesions tend to occur on the face, flexures and limbs not covered by clothing.
Features
Features
- 'golden', crusted skin lesions typically found around the mouth
- very contagious
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| © Image used on license from DermNet NZ | |
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| © Image used on license from DermNet NZ | |
Management
Limited, localised disease
Extensive disease
- topical fusidic acid is first-line
- topical retapamulin is used second-line if fusidic acid has been ineffective or is not tolerated
- MRSA is not susceptible to either fusidic acid or retapamulin. Topical mupirocin (Bactroban) should, therefore, be used in this situation
Extensive disease
- oral flucloxacillin
- oral erythromycin if penicillin-allergic
- children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment