Group A Streptococcal Infections

Group A streptococcal infections are caused by a group of bacteria in the streptococcus family. These infections include strep throat, scarlet fever, and others.

What is going on in the body?

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:

What are the causes and risks of the infection?

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 in children is now known to be a risk for serious GAS disease.

What are the signs and symptoms of the infection?

Strep throat is the most common of the GAS infections. Following are some of the symptoms of strep throat:

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 septic arthritis attacks joints.

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

How is the infection diagnosed?

Infected material from the throat, blood, or a wound can be cultured. A culture is a 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.

What can be done to prevent the infection?

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.

What are the long-term effects of the infection?

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.

What are the risks to others?

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.

What are the treatments for the infection?

Penicillin, amoxicillin, and other antibiotics are used to treat GAS infections. To prevent complications, it is important to take the full course of the prescribed antibiotics.

What are the side effects of the treatments?

Antibiotics can cause stomach upset and allergic reactions.

What happens after treatment for the infection?

Most GAS infections respond rapidly to treatment. Once the antibiotics are finished and symptoms resolve, no further treatment is usually needed. Additional treatment may be needed if the person has complications such as rheumatic fever.

How is the infection monitored?

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.

Author:Danielle Zerr, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:04/30/01
Reviewer:Eileen McLaughlin, RN, BSN
Date Reviewed:04/04/01