Streptococcus A (strep A)

Group A Streptococcus (GAS), also known as Strep A, are bacteria commonly found on the skin or in the throat. Under some circumstances these bacteria can cause disease.

GAS infection commonly presents as a mild sore throat ('strep throat') and skin/soft tissue infections such as impetigo and cellulitis.

Immediate action required: Phone 999 or go to A&E if:

  • your child is having difficulty breathing (you may notice grunting noises or their tummy sucking under their ribs)
  • there are pauses when your child breathes
  • your child's skin, tongue or lips are blue
  • your child is floppy and will not wake up or stay awake

Urgent advice: Contact your GP if your child:

  • is getting worse
  • is feeding or eating much less than normal
  • has had a dry nappy for 12 hours or more or shows other signs of dehydration
  • is under 3 months and has a temperature of 38°C
  • is older than 3 months and has a temperature of 39°C or higher
  • feels hotter than usual when you touch their back or chest, or feels sweaty
  • is very tired or irritable

If your GP is closed, contact the 111 service.

If you feel that your child is seriously unwell, trust your own judgement and seek medical assistance.

GAS infections

GAS bacteria can cause a wide variety of skin, soft tissue and respiratory tract infections ranging in severity from mild to life-threatening. These include:

In rare cases, patients may go on to develop post-streptococcal complications, such as:

  • rheumatic fever
  • glomerulonephritis (heart and kidney diseases caused by an immune reaction to the bacteria)

iGAS infections

GAS can very rarely cause more serious conditions, known as invasive group A Streptococcus (iGAS) infections. These can include:

  • bacteraemia (an infection of the bloodstream)
  • septic arthritis
  • meningitis
  • necrotising fasciitis (a severe infection involving death of areas of soft tissue below the skin)
  • Streptococcal toxic shock syndrome (rapidly progressive symptoms with low blood pressure and multi-organ failure)

iGAS infections tend to happen in the elderly, the very young, or people with an underlying risk factor such as injecting drug use, alcoholism, immunosuppression or cancer.

Preventing GAS infection

GAS are spread by close contact between individuals, through respiratory droplets (moisture in your breath) and direct skin contact.

To help reduce the risk of picking up or spreading infections:


  • wash your hands properly with soap for 20 seconds
  • use a disposable tissue to catch coughs and sneezes
  • keep away from others if you feel unwell


  • do not share contaminated food, utensils, cups and glasses, baths, bed linen or towels

Last updated:
07 December 2022