Impetigo (school sores)

Notification requirement for impetigo (school sores)

Notification is not required.

Primary school and children’s services centres exclusion for impetigo (school sores)

Exclude until appropriate treatment has commenced. Sores on exposed surfaces must be covered with a watertight dressing.

Infectious agent of impetigo (school sores)

Various strains of Streptococcus pyogenes, group A streptococci (GAS) and Staphylococcus aureus cause impetigo.

Identification of impetigo (school sores)

Clinical features

Impetigo is a contagious, superficial skin infection seen mainly in children, but it may occur at any age. The infection may present with mildly irritating blisters that become pustular and erode rapidly, leaving a honey-coloured crust. It often appears around the nose and mouth.

Local lymph nodes may be enlarged, and the affected child may occasionally be acutely ill.

Impetigo due to S. pyogenes is very occasionally associated with scarlet fever and may also rarely cause a glomerulonephritis. Glomerulonephritis usually occurs 3–8 weeks after the skin infection. Skin GAS infections may be an important risk factor for rheumatic heart disease, independent of throat GAS carriage.

Impetigo in the neonate often follows S. aureus colonisation of the nose, umbilicus, rectum or conjunctivae. The lesions are initially vesicular, and become seropustular and may develop bullae (bullous impetigo). Lesions are most common in the nappy area. Complications are rare.

Staphylococcal skin infections rarely result in the more severe ‘scalded skin syndrome’, which varies from a diffuse scarlatiniform erythema to a generalised bullous desquamation of the skin.

Diagnosis

Diagnosis should be confirmed by isolation of the organism from skin swabs. This also allows confirmation of antibiotic susceptibility.

Incubation period of impetigo organisms

The incubation period is 1–3 days for S. pyogenes and 4–10 days for S. aureus.

Public health significance and occurrence of impetigo (school sores)

Occurrence is worldwide. Impetigo is a rapidly spreading, highly contagious skin infection that frequently occurs in children’s settings such as day-care centres, kindergartens and schools.

Reservoir of impetigo organisms

Humans are the reservoir.

Mode of transmission of impetigo organisms

The organisms enter through damaged skin and are transmitted through direct contact with patients or asymptomatic carriers. Nasal carriers are particularly likely to transmit disease. The disease is rarely transmitted by indirect contact with objects.

Period of communicability of impetigo (school sores)

If untreated, purulent discharges may remain infectious for weeks to months.

Most cases are no longer infectious after 24 hours of appropriate antibiotic therapy.

Susceptibility and resistance to impetigo (school sores)

Everyone is susceptible to streptococcal and staphylococcal skin infections.

People suffering from chronic conditions producing breaks in the skin, such as eczema or atopic dermatitis, may be at greater risk of impetigo.

Control measures for impetigo (school sores)

Preventive measures

Preventive measures include good personal hygiene practices, including a daily bath or shower. Emphasise the importance of not sharing toilet articles, and of suitably covering cuts and abrasions.

Educate on modes of transmission and possible complications of impetigo, and reinforce the importance of treating cases promptly.

Control of case

Wash the lesions with soap and water every 8 hours to soften crusts.

For cases where Streptococcus pyogenes is suspected or confirmed, treatment is generally phenoxymethylpenicillin or benzathine penicillin.

Patients with penicillin hypersensitivity are generally given clindamycin.

For cases where Staphylococcus aureus is suspected or confirmed, mupirocin ointment is the usual treatment.

For severe, widespread or longstanding infections, flucloxacillin, amoxicillin–clavuanate or cephalexin may be used, as each of these drugs is active against both S. aureus and S. pyogenes. When resistant organisms such as methicillin-resistant S. aureus (MRSA) are suspected, intravenous vancomycin may be required, or oral therapies such as bactrim or clindamycin, if susceptible.

In all cases, see the current edition of Therapeutic guidelines: antibiotic.

General advice for patients with impetigo includes:

• dispose of soiled dressings appropriately
• emphasise the need for handwashing, especially after changing dressings, and the importance of avoiding sharing toilet articles, towels, clothing or bed linen
• avoid scratching or touching the lesions, to prevent spread to other areas of the body
• advise on the importance of completing the recommended antibiotic course.

Patients must be excluded from school or childcare services until antibiotic treatment has commenced. Sores on exposed surfaces such as scalp, face, hands or legs must be covered with a watertight dressing.

Control of contacts

Advice to household members should include:

• educating about the mode of transmission
• avoiding direct contact with lesions on the affected person, if possible
• remembering to wash hands regularly, particularly after touching the lesions or scabs of the infected person, and using gloves where possible
• referring symptomatic contacts for appropriate treatment.

Control of environment

See ‘Control of contacts’.

Outbreak measures for impetigo (school sores)

In childcare settings and schools:

• Exclude all confirmed cases, and refer suspected cases for appropriate treatment and management.
• Emphasise the need for good handwashing procedures for all staff and children.
• Advise parents of other children and staff who may have had contact with the cases to remain vigilant for signs of impetigo and seek treatment if symptoms develop.
• Ensure that sores on exposed skin surfaces of confirmed cases are covered with a watertight dressing while at school.
• Cohort cases and contacts until all have been discharged. Staff working with colonised infants should not work with noncolonised newborns.
• Obtain swabs from discharging lesions to determine the organism.
• Treat confirmed cases with appropriate antibiotics.
• Draining lesions should be covered at all times with a dressing.

In hospital nurseries or maternity wards:

• Trace and determine source of infection and consider
  • examining staff for active lesions anywhere on the body
  • obtaining nasal swabs from staff to detect asymptomatic carriers, and treating accordingly.
• Promote the need for good handwashing and hygiene practices among staff and visitors to the unit where the outbreak has occurred.
• Investigate the adequacy of infection control procedures and the availability of handwashing facilities, including antiseptic hand solutions.