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Invasive group A streptococcal infections: management of household contacts

  • See also

    Skin and Soft Tissue Infections
    Pleural Effusion and Empyema
    Sore Throat
    Osteomyelitis and Septic Arthritis

    Key points

    • Invasive Group A Streptococcal disease (iGAS) is associated with significant morbidity and mortality
    • There is an increased risk of secondary cases of iGAS in household contacts of an index case
    • Household contacts require education about this increased risk and chemoprophylaxis should be considered


    Group A streptococcus (GAS) (also known as Streptococcus pyogenes) commonly colonises the skin, nasopharynx or anogenital tract of children.
    GAS causes a wide range of clinical disease in children, from mild illnesses such as pharyngitis and impetigo, to severe, life-threatening invasive infections. 

    Invasive GAS Disease (iGAS)

    iGAS is defined by the isolation of GAS from a normally sterile site. Manifestations include: 

    • Bacteraemia/septicaemia
    • Streptococcal Toxic Shock Syndrome (STSS)
    • Necrotising fasciitis
    • Pneumonia/ Empyema
    • Retropharyngeal abscess
    • Osteomyelitis / Septic arthritis
    • Meningitis

    Cellulitis and pharyngitis are not considered to be invasive disease.

    Management of household contacts of a case of iGAS

    Household contacts - those who have spent more than 24 hours in the same house as an index case in the 7 days prior to symptom onset.
    They are at increased risk of iGAS compared with the general population.
    Secondary cases usually occur within a month of the index case, and predominantly in the first 7 days.

    Some experts and guidelines recommend antibiotic chemoprophylaxis to reduce the risk of iGAS in household contacts, although this has not been studied.

    Regardless of whether chemoprophylaxis is prescribed, all household contacts should be educated about their increased risk of iGAS, and the early signs and symptoms of iGAS that require prompt medical evaluation. These include:

    • High fevers
    • Severe muscle aches
    • Sore throat
    • Cellulitis
    • Diarrhoea or Vomiting
    • Severe Headache

    Assessment & Management



    This guideline relates only to household contacts. For management of other close contacts, including nosocomial cases, local expert advice should be sought