Group A streptococcal disease (GAS) is caused by a bacterium (germ) called Streptococcus pyogenes,group A. People may carry the germ on their skin or in their noses and throats and have no symptoms of illness. Most often, Group A streptococcal infections are mild illnesses such as “strep throat” or impetigo. Sometimes, the bacteria invade the lungs (pneumonia), blood (septicemia), or spread along the layers of tissue that surround muscle (called the fascia). These infections are called invasive Group A streptococcal (iGAS) disease and are very serious, even life-threatening. 

Two of the most severe, but least common, forms of iGAS are necrotizing fasciitis and streptococcal toxic shock syndrome. Necrotizing fasciitis, also known as "flesh-eating disease," is a rapidly progressing disease which destroys muscles, fat, and skin tissue. Streptococcal toxic shock syndrome results in a rapid drop in blood pressure and causes organs such as the kidneys, liver, or lungs to stop working.

Symptoms of septicemia (blood poisoning) include fever, chills, headache, generally not feeling well, pale skin, lack of energy, rapid breathing, and increased heart rate. 

Early symptoms of necrotizing fasciitis include severe pain and swelling, often rapidly getting worse; fever; redness around a wound.

Early symptoms of streptococcal toxic shock syndrome include fever; sudden severe pain, often in an arm or leg; dizziness; confusion; feelings of having “the flu"; and a  flat red rash over large areas of the body.

The bacteria are spread from person to person through close personal contact with the nose and throat secretions of an infected person:

• Breathing in air contaminated with streptococcal bacteria when an infected person has coughed, sneezed, or talked
• Kissing, sharing drinking cups, forks, spoons, or cigarettes
• Touching the nose and throat secretions of an infected person
• Touching articles recently contaminated with the nose and throat secretions of an infected person

People with chronic illnesses such as cancer, diabetes, and chronic heart or lung disease, and those who use medications such as steroids have a higher risk for iGAS. Persons with cuts to the skin, wounds, or chicken pox, the elderly, and adults with a history of alcohol abuse or injection drug use also have a higher risk for disease.

• 10 to 15 people out of 100 will die from their infection
• 25 people out of 100 with necrotizing fasciitis will die
• More than 35 people out of 100 with streptococcal toxic shock syndrome will die 

Diagnosis is made by a test of blood, cerebrospinal fluid, or tissue from deep inside a wound.

The case is usually hospitalized and is treated with antibiotics. For persons with necrotizing fasciitis, early and aggressive surgery is often needed to remove damaged tissue and stop the spread of the disease.

Close contacts of severe cases are also offered antibiotics to prevent them from getting sick.

There is no vaccine to prevent group A streptococcal infections.

Antibiotics are recommended for certain close contacts of severe cases of iGAS (for example, persons living in the same household).

Wash hands well, especially after coughing and sneezing and before preparing foods or eating.

Keep all cuts and wounds clean and watch for possible signs of infection such as redness, swelling, drainage, and pain at the wound site.

If there are signs of an infected wound, especially with fever, see a doctor as soon as possible.