Group A streptococcus
Information and guidance on group A streptococcal infections.
This group A streptococcus collection also contains information on:
Infection and symptoms
Group A streptococcus (also known as GAS, group A strep, strep A, Streptococcus pyogenes) is a bacterium which can colonise the throat, skin and anogenital tract. It is spread by close contact between individuals, through respiratory particles and direct skin contact. It can also be transmitted environmentally, for example through contact with contaminated objects, such as towels or bedding, or ingestion of food prepared by someone with the infection.
GAS causes a diverse range of skin, soft tissue and respiratory tract infections, including:
- tonsillitis
- pharyngitis
- scarlet fever
- impetigo
- erysipelas
- cellulitis
- pneumonia
Occasionally these infections can be extremely severe.
Scarlet fever is characterised by a rash, which usually accompanies a sore throat. Cases may also have a red and swollen tongue and flushed cheeks.
Invasive GAS (iGAS) is another infection caused by GAS, that is much rarer than scarlet fever. It occurs when GAS is isolated from a normally sterile body site, such as the blood.
Both iGAS and scarlet fever are notifiable diseases: health professionals must inform local health protection teams (HPTs) of suspected cases.
Information for the public
Members of the public can seek advice about group A streptococcal infections from the following:
- NHS guidance on group A streptococcal infections
- NHS guidance for parents of babies or toddlers who may be seriously ill
- NHS guidance on looking after sick children
- Royal College of Paediatrics and Child Health (RCPCH) statement on group A streptococcal infections and scarlet fever
The latest UKHSA updates for the public are also available on GOV.UK:
Guidance for professionals
Interim clinical guidance on the diagnosis and treatment of children was published on 2 December 2022 by NHS England.
Prevention and control of group A streptococcal infection in acute healthcare and maternity settings in the UK was published in 2011 by the Health Protection Agency.
Diagnosis
GAS is formally diagnosed by microbiological culture of samples taken from the affected site. Serology has specific clinical uses and can be discussed with a local infection specialist. GAS isolates from patients with healthcare-associated infections should be stored locally for a minimum of 6 months.
Epidemiology and reports
Previous activity reports on group A streptococcal infections were published by Public Health England. The following are UKHSA reports:
Last updated 16 December 2022 + show all updates
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Updated background information and provided links for people seeking medical advice.
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Added Group A streptococcal infections: activity during the 2022 to 2023 season.
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Added Group A streptococcal infections: activity during the 2021 to 2022 season.
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Added link 'Invasive group A streptococcal outbreaks associated with home healthcare'.
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Updated link under Diagnosis to AMRHAI, which now provides diagnostic services.
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Added 'Group A streptococcal infections: activity during the 2018 to 2019 season' document.
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Latest seasonal activity document inserted into the Epidemiology subgroup (2017/2018 season)
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Added report on activity during the 2014 to 2015 season under epidemiology.
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Added 'Group A streptococcal infections: activity during the 2014 to 2015 season' to the collection.
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First published.