Information about Group A Strep infections

Group A streptococcus, also called Group A Strep or GAS, is a common bacterium that often lives on people’s skin or in their throats.  

It doesn’t always cause illness but can cause mild infections or, in very rare cases, a severe and life-threatening infection. 

What kind of mild infections does GAS cause? 

A mild GAS infection will usually affect the skin, soft tissues and respiratory tracts – for example tonsilitis, pharyngitis and impetigo are all caused by GAS. 

GAS also causes scarlet fever, a flu-like infection that’s accompanied by a sore throat, swollen neck glands and a rash that develops 12-48 hours later. Scarlet fever is primarily a childhood disease, with around 90% of cases occurring in children under 10. We are currently seeing high numbers of scarlet fever cases in the UK, which is most likely due to various factors including increased social mixing and increases in other respiratory viruses. 

These conditions, although unpleasant, are relatively mild and can be treated easily with antibiotics.  

What kind of serious infections does GAS cause, and who is most at risk? 

The most serious infections linked to GAS come from invasive Group A Strep, or iGAS. These happen when bacteria enter the body through an open would or sore, through a damaged respiratory system, or because a person’s immunity is compromised. iGAS can cause infections such as Streptococcal Toxic Shock Syndrome, which are serious and need prompt medical attention. 

Those most at risk from iGAS infections are the very young, the elderly, and those with an underlying condition such as a compromised immune system, other serious illness such as cancer, or drug or alcohol dependency. It’s important to stress that the risk of iGAS infections in young adults is very low, but as with any illness you should seek medical advice if you have symptoms. 

What are the symptoms of a GAS or iGAS infection and what should you do if you think you, or a friend, are affected? 

Common symptoms of a GAS infection include: 

• Flu-like symptoms, such as a high temperature, swollen glands or an aching body 
• Sore throat (tonsilitis or ‘strep throat’) 
• A rash that feels rough, like sandpaper (scarlet fever) 
• Scabs and sores (impetigo) 
• Pain and swelling (cellulitis) 
• Severe muscle aches 
• Nausea and vomiting 

If you’re suffering from any of these symptoms please contact your GP surgery or call NHS 111 as soon as possible. 

Get medical help immediately (go to the nearest hospital with an Accident and Emergency department or call 999 for an ambulance) if: 

• You have difficulty breathing 
• You feel weak and ‘floppy’, or like you can’t stay awake 
• Your skin, tongue or lips turn blue 
• You become dizzy or confused 

How to avoid spreading GAS and other infections 

Infections like Strep A are easily spread by close contact with an infected person. To reduce the risk of infection make sure you practice good hygiene, for example: 

• Washing your hands often with soap and water 
• Covering your mouth and nose with a tissue when you cough or sneeze 
• Throwing used tissues into the bin as quickly as possible 
• Limiting contact with others if you feel unwell 

Further information

• NHS: Strep A 
• UK Health Security Agency: Group A Strep – what you need to know 
• NHS: Scarlet Fever 
• UCL Student Support and Wellbeing: Registering with a GP