Group A Streptococcal Infections

Group A streptococcal, or GAS, bacteria are often found on the skin and in the throat of healthy individuals. Most of the time, GAS bacteria cause no symptoms at all. At other times, these bacteria affect various parts of the body and cause an infection.

GAS infections include the following:

• necrotizing fasciitis, a destructive, rapidly progressing infection of the deep tissue layers that is also known as "flesh-eating bacteria"
• pneumonia
• scarlet feverin which a toxin causes a rash after a streptococcal infection
• septic arthritisa joint infection
• skin infections, including impetigo and cellulitis
• strep throat
• streptococcal toxic shock syndrome (TSS), a life-threatening infection of the bloodstream

Strep throat is the most common of the GAS infections. Some of the symptoms of strep throat include:

• fever, with a temperature of 101 to 104 degrees Fahrenheit (38.3 to 40 degrees Celsius)
• headache
• painful swallowing
• sore throat that starts suddenly, without runny nose or congestion
• swollen lymph nodes in the neck
• white patches on the tonsils

Symptoms of other GAS infections depend on the type of infection and the part of the body that is involved.

Impetigo, for example, causes an infection of the top skin layers. Cellulitis is a more serious infection that involves deeper skin layers and underlying tissue.

Pneumonia is a lung infection, and if the infection involves a joint, it is termed septic arthritis.

Some GAS infections, especially blood infections, can be severe. These infections can be associated with streptococcal toxic shock syndrome. In this syndrome, the blood pressure drops and the liver, kidney, lungs, and clotting system can fail rapidly.

GAS infections are caused by certain strains of streptococcal bacteria. People who have underlying diseases such as diabetes can have more serious infections. Those with weakened immune systems are at higher risk. Chickenpox infection is now known to place children at higher risk for serious GAS disease.

Anyone with a GAS infection should take antibiotics for at least 24 hours before returning to work, school, or day care. Good hand-washing is also important to prevent spread of a GAS infection.

Infected material from the throat, blood, or a wound can be cultured. A culture is a tissue or fluid sample that is tested for bacterial growth. Throat cultures are used to diagnose strep throat or scarlet fever. An antibody titer test may be used to look for antibodies to GAS.

Severe streptococcal infections may cause loss of body tissue or even death. Rheumatic fever is a complication of strep throat caused by certain types of GAS. It can cause permanent heart damage. Poststreptococcal glomerulonephritis is another complication of a GAS infection. It causes kidney damage, high blood pressure, and body swelling.

Group A streptococcal infections are contagious. They can be spread through direct contact with mucus from the nose or throat of an infected person. The bacteria can also be spread by direct contact with discharge from contaminated wounds or skin lesions.

Penicillin (i.e., Pen VK), amoxicillin (i.e., Amoxil), erythromycin (i.e., EES), cephalexin (i.e., Keflex), azithromycin (i.e., Zithromax), clarithromycin (i.e., Biaxin) and other antibiotics are used to treat GAS infections. To prevent complications, it is important to take the full course of the prescribed antibiotics. Necrotizing fasciitis demands surgical excision of the tissue that has been destroyed, followed by open drainage of the wounds. Streptococcal toxic shock syndrome must be treated with vigorous life support measures to give antibiotics time to work against the infection.

Antibiotics can cause stomach upset and allergic reactions.

Most GAS infections respond rapidly to treatment. Once the antibiotics are finished and symptoms resolve, no further treatment is usually needed. Additional treatment, supportive care, and rehabilitation may be needed during the recovery phase from complications such as rheumatic fever, glomerulonephritis, toxic shock syndrome, or necrotizing fasciitis.

Usually, monitoring is only short-term, to make sure the infection has cleared. Other monitoring may be needed for more serious infections or complications. Any new or worsening symptoms should be reported to the healthcare provider.