Group A Streptococcal Infections

Group A streptococcal (GAS) infections occur when bacteria enter your body and causes an illness. Most illnesses are mild and affect the skin and throat. The GAS bacteria is contagious and spreads easily. Antibiotics treat group A streptococcal infections.

Overview

What are group A streptococcal infections?

Group A streptococcal (GAS) infections occur when a microorganism (bacteria) enters your body and causes an illness, most often in your skin and throat. There are more than 120 strains of group A Streptococcus bacteria, which is the bacteria that causes group A streptococcal infections.

The majority of illnesses caused by GAS bacteria are mild. Sometimes, GAS infections cause severe, life-threatening symptoms if you don’t receive treatment.

Advertisement

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

What are the types of group A streptococcal infections?

There are several types of group A streptococcal (GAS) infections that can range from mild infection, like a sore throat, to severe or life-threatening conditions.

Mild Strep infections

Mild illnesses include:

  • Cellulitis: An infection that targets tissues deep beneath your skin.
  • Erysipelas: An infection that targets the top layers of skin.
  • Impetigo: Sores and blisters that form near your mouth and nose or on your arms and legs.
  • Sore throat: Pain and discomfort in your throat.
  • Strep throat: An infection in your throat and tonsils.

Severe Strep infections

Certain types of group A strep bacteria can cause severe infections including:

  • Bloodstream infections (bacteremia).
  • An infection that causes a rash, sore throat and a high fever (scarlet fever).
  • Multi-organ infections (toxic shock syndrome).
  • Inflamed tissues in your joints and heart (rheumatic fever).
  • Flesh-eating disease (necrotizing fasciitis).

Who do group A streptococcal infections affect?

Advertisement

Group A streptococcal infections can affect anyone since the bacteria easily spreads from person to person. People who have a GAS infection are contagious while they’re ill. They can pass the bacteria to you by coughing or sneezing or you can get the bacteria if you come into contact with an infected part of their skin (lesion).

How common are group A streptococcal infections?

An estimated 10 million mild group A streptococcal infections that affect the throat and skin occur every year.

Symptoms and Causes

What are the symptoms of group A streptococcal infections?

Symptoms range in severity and vary based on the illness that the group A streptococcus bacteria caused. Mild symptoms of group A streptococcal infection include:

Skin infection symptoms

Symptoms that affect the skin from a group A streptococcal infection include:

  • Rash on your neck, underarms or groin.
  • Small, red to purple sores on the nose, mouth, arms and legs.
  • Itchy skin.
  • Sores that leak a clear to yellow fluid or pus.
  • Crusty yellow scabs form over the sores.

Severe symptoms

Severe symptoms of a group A streptococcal infection include:

Advertisement

What causes group A streptococcal infections?

Group A Streptococcus bacteria causes group A streptococcal infections.

Your immune system is responsible for defending your body from outside invaders, like bacteria, that cause illness. When bacteria enter your body, you experience symptoms. At the same time, your immune system works to destroy the bacteria to limit the amount of harm it does to your body.

Sometimes your immune system needs a little bit of help to destroy bacteria that are in your body, which is why your healthcare provider will offer medicine like antibiotics to reduce your symptoms faster.

Is group A streptococcus bacteria contagious?

Yes, group, A Streptococcus bacteria is contagious. The bacteria spread through contact with someone who has a GAS infection including:

  • Breathing in droplets of the bacteria released into the air after a cough or sneeze.
  • Contacting discharge (saliva or mucus) from someone’s nose or mouth.
  • Drinking from the same glass or sharing utensils with someone who is sick.
  • Touching someone’s infected wound (lesion) or skin sore.

The bacteria is most contagious when you experience symptoms of being sick. You can prevent the spread of GAS bacteria by staying home if you’re sick, wearing a mask and treating any wounds you might have.

Diagnosis and Tests

How are group A streptococcal infections diagnosed?

Diagnosis is dependent on what type of infection you have. First, your provider will check your symptoms and offer a physical exam. They'll ask you questions about your symptoms like how long you’ve had them and how severe they are.

Your provider will offer tests to confirm a diagnosis including:

  • A blood test to look for an infection.
  • A rapid test or culture test that swabs your throat and looks for bacteria under a microscope.
  • A tissue sample to look for an infection in a biopsy.
  • An imaging test like an MRI, CT scan or ultrasound to look at the damage underneath your skin caused by the infection.

Management and Treatment

How are group A streptococcal infections treated?

Antibiotics usually treat group A streptococcal infections. There are two types of antibiotics that your provider will give you to treat your infection depending on what type of infection you have. You might receive a cream that you rub onto your sores (topical) or antibiotics in the form of a pill (oral).

Antibiotics offer several benefits to help you feel better after infection including:

  • Shortening the length of your illness.
  • Minimizing symptoms.
  • Preventing the bacteria from spreading.
  • Preventing complications and serious illness.

Are there vaccines for group A streptococcal infections?

There are no vaccines available to prevent group A streptococcal infections, but vaccines are currently in development.

What medications treat group A streptococcal infections?

There are several types of medicines available to treat group A streptococcal infections including:

How soon after treatment will I feel better?

It could take between three to five days until you start to feel better after taking antibiotics to treat a group A streptococcal infection. Symptoms should reduce after a few days if you have a mild infection. Severe infections could take up to two weeks until you start to feel better.

Prevention

How can I reduce my risk of spreading or getting group A streptococcal infections?

Even though there is no vaccine to prevent group A streptococcal infections, you can reduce your risk of getting an infection or spreading infection by having good hygiene. Good hygiene includes:

  • Washing your hands with soap and water often.
  • Covering your mouth and nose when you cough or sneeze.
  • Throwing away your tissues after using them.
  • Washing utensils, plates and glasses after someone who is sick uses them.
  • Staying home if you feel sick.
  • Cleaning and covering wounds until they heal.

Outlook / Prognosis

What can I expect if I have a group A streptococcal infection?

If you have a group A streptococcal infection, you could feel ill for several days until your antibiotics and your immune system target the bacteria in your body. While you’re sick, make sure you stay home and rest until your symptoms reduce to prevent the spread of the bacteria.

If you get a group A streptococcal infection, there is a chance that you could get the infection again in the future if you’re exposed to the bacteria.

Are there any serious complications that could happen after an infection?

While rare, some strains of the group A Streptococcus bacteria from an infection can spread to other parts of your body, which can cause complications including:

Group A streptococcal infections can be dangerous for people who are pregnant and young children. If you are pregnant and experience symptoms or if your child shows symptoms of a group A streptococcal infection, visit your healthcare provider immediately.

Living With

When should I see my healthcare provider?

Visit your healthcare provider if you have serious symptoms, your infection gets worse or your symptoms don’t go away after two weeks with treatment.

What questions should I ask my doctor?

  • How often should I take antibiotics?
  • What type of infection do I have?
  • What type of antibiotics can I take if I have a penicillin allergy?
  • How should I take care of my wound until it heals?

A note from Cleveland Clinic

Group A streptococcal infections cause temporary illnesses that are easily treated with antibiotics. If you experience symptoms, visit your healthcare provider to receive treatment to minimize the amount of time you’ll feel under the weather. Infections can be serious and spread to other parts of your body, so don’t delay getting treatment.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 05/02/2022.

Learn more about our editorial process.

Ad
Questions 216.444.2538