Streptococcal infection - group A

About group A streptococcal infection

Group A Streptococcus (GAS) is a type of bacteria that can cause a broad range of infections and complications which vary from mild to severe. GAS is also known as Group A Strep, Strep A and Streptococcus pyogenes.

Commonly, it causes throat infection (pharyngitis), tonsil infection (tonsillitis), scarlet fever, skin sores (impetigo) and skin infection (cellulitis).

Rarely, it can cause serious, potentially life-threatening infections which are also known as invasive group A streptococcal disease (iGAS).

Complications of GAS infection include kidney disease (glomerulonephritis) and acute rheumatic fever which can lead to skin, joint, heart (rheumatic heart disease) and brain problems.

Symptoms of group A streptococcal infection

Symptoms vary depending on the type of infection.

Some people carry the bacteria in their respiratory tract or on their skin without symptoms or signs of infection.

Streptococcal throat infection

Streptococcal throat infection is also known as strep throat.

Symptoms of throat infection (pharyngitis) and tonsil infection (tonsillitis) include:

• sore, red throat or tonsils
• pus on throat or tonsils
• pain on swallowing
• fever and chills
• swollen and tender lymph nodes (glands) in the neck
• vomiting, nausea and abdominal pain
• headache and muscle aches
• general feeling of unwell (malaise)
• loss of appetite

Scarlet fever

Some people with streptococcal throat infection can develop scarlet fever. It usually affects school-aged children.

Symptoms of scarlet fever are similar to streptococcal throat infection (listed above) and also include:

• a pink or red (scarlet) skin rash that usually starts on the face and neck, spreads to the arms, legs and body and tends to be more noticeable around skin folds such as the armpits, groin, elbows and knees. The rash looks like sunburn and feels like sandpaper.
• a flushed face with paleness around the mouth
• a bright red and bumpy tongue, also known as a strawberry tongue

If left untreated it can lead to serious illness and complications such as acute rheumatic fever. Treatment is with antibiotic medication.

Streptococcal skin infection

GAS bacteria can cause skin infections such as impetigo and cellulitis.

Impetigo is common in school aged children and is also known as school sores. Symptoms of impetigo include:

• itchy, red skin with blisters that crust and scab. It usually affects the skin around the nose and mouth and the legs
• swollen and tender lymph nodes
• fever

Symptoms of cellulitis include:

• redness, warmth, swelling and tenderness or pain of the skin
• swollen and tender lymph nodes
• fever

Treatment is with antibiotic medication.

Invasive group A streptococcal disease (iGAS)

GAS can cause rare but serious and potentially life-threatening infections when it invades parts of the body that normally do not have bacteria in them (sterile site). These severe forms of infection are called invasive group A streptococcal disease (iGAS) and include:

• lung infection (pneumonia)
• blood infection (bacteraemia or septicaemia)
• central nervous system infection (meningitis)
• bone or joint infection (osteomyelitis or septic arthritis)
• flesh-eating infection (necrotising fasciitis)
• toxic shock syndrome
• infection during pregnancy or post-partum (maternal sepsis)

Symptoms vary depending on the type of infection and can include:

• fever and chills
• general feeling of unwell (malaise)
• dizziness
• headache and muscle aches
• breathlessness and chest pain
• neck stiffness and light sensitivity (photophobia)
• vomiting, nausea and abdominal pain
• redness, warmth, swelling and tenderness or pain at the infection site
• bleeding, pus or ulceration at the infection site

People with iGAS are usually very unwell. Urgent medical care and treatment in a hospital is usually required.

Complications of group A streptococcal infection

GAS infection can result in serious complications caused by abnormal immune responses following the infection.

Acute rheumatic fever and rheumatic heart disease

Acute rheumatic fever is a disease that can occur from untreated GAS infection. It causes inflammation in many parts of the body, including the skin, joints, heart and brain and can lead to long-term health problems such as rheumatic heart disease (a disease of the heart valves).

While only a small number of people develop acute rheumatic fever, parts of Australia, such as Northern Territory, and certain groups such as Aboriginal and Torres Strait Islander people are at increased risk.

Prevention, early diagnosis and treatment are important to reduce the risk of acute rheumatic fever. Preventing recurrent GAS infections helps reduce the risk of rheumatic heart disease.

Kidney disease

A rare kidney disease called post-streptococcal glomerulonephritis can occur from abnormal immune responses following GAS infection. It usually occurs 1 to 3 weeks following the initial GAS infection and is more common in children than adults.

Symptoms include dark and discoloured urine, reduced urination, swelling (especially in the face, around the eyes, and the hands and feet), and feeling tired (fatigue). Some people have no or mild symptoms.

It is diagnosed by the doctor through clinical examination and laboratory testing of the urine and blood to check kidney function and testing to detect the bacteria.

Treatment is mainly aimed at controlling swelling and blood pressure and may include antibiotic medication. Most people recover within a few weeks but some people can have long-term kidney problems.

Spread of group A streptococcal infection

GAS is spread from person-to-person through:

• respiratory droplets such as from coughing, sneezing or talking
• contact with bacteria on the skin
• contact with bacteria on contaminated surfaces or objects

People who carry the bacteria but without symptoms can still potentially spread infection to others.

Outbreaks can occur in childcare settings, residential care facilities and hospitals.

Risk factors for group A streptococcal infection

GAS infection can occur in people of all ages. People who come into contact with someone with GAS infection are at increased risk.

Streptococcal throat infection, scarlet fever and impetigo are more common in school aged children.

iGAS is rare but some people are at increased risk, including:

• household contacts of someone with iGAS (within the past 30 days)
• the elderly and young infants
• Aboriginal and Torres Strait Islander people
• people who inject drugs
• people who have a weakened immune system or chronic disease

Preventing group A streptococcal infection

The best way to protect against getting or spreading GAS infection is to practice good hand washing and personal hygiene. People with GAS infection should not share utensils or prepare food for others while unwell.

People who have been exposed to GAS bacteria and have an increased risk of infection, serious illness or are part of an outbreak may be recommended to receive preventive antibiotic medication.

Children with group A streptococcal infection

Children with GAS infection must not go to school, kindergarten, childcare or other children’s settings until they have received at least 24 hours of antibiotic treatment and feel well. It is important to complete the entire course of antibiotic treatment.

Children with impetigo should have all exposed blisters covered with a watertight dressing before returning to school, kindergarten, childcare or other children’s settings.

Diagnosis of group A streptococcal infection

GAS infection is diagnosed by a doctor through clinical examination and laboratory testing to detect the bacteria.

The sample used for laboratory testing depends on the type of infection. Samples may include a throat swab, skin swab, blood, cerebrospinal fluid or other bodily fluid or tissues.

Treatment of group A streptococcal infection

Treatment is mainly through antibiotic medication.

It is important to complete the course of antibiotic treatment as prescribed by your doctor. Untreated infection can lead to serious illness and complications and can spread infection to others.

Where to get help

• Your GP (doctor)
• Emergency department of your nearest hospital
• NURSE-ON-CALL. Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)
• Infectious Diseases, Department of Health. Tel. 1300 651 160