Streptococcus Pyogenes (Strep A): Illnesses & Diagnosis

Streptococcus pyogenes, or Strep A, is a bacteria that can cause pharyngitis and tonsillitis. It can also cause more severe infections, like scarlet fever, rheumatic fever, and toxic shock syndrome. 

Strep A is naturally present in the mouth, throat and respiratory system, even without an infection. Therefore, it is easily transmitted from person to person through cutlery sharing, secretions, or coughing or sneezing. 

Symptoms of an infection vary depending on where the bacteria is most concentrated, which is usually in the skin and throat. Treatment for strep A is usually done with antibiotics prescribed by a doctor, however very severe infections may require surgical intervention. 

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Strep A illnesses

The main illnesses that Strep A can cause are: 

1. Pharyngitis

Bacterial pharyngitis is a throat inflammation caused by Streptococcus bacteria, particularly Streptococcus pyogenes. It is important for pharyngitis to be identified and treated to prevent complications like rheumatic fever.  Learn more about the symptoms of strep throat and what can cause it. 

Symptoms: The most common symptoms of bacterial pharyngitis are intense sore throat, painful lumps on the side of the neck, difficulty swallowing, loss of appetite and high fever. 

Treatment: Treatment for bacterial pharyngitis involves the use of antibiotics for about 10 days, depending on the doctor’s evaluation. He or she may also prescribe additional medication to decrease inflammation and relieve symptoms. 

2. Tonsillitis

Tonsillitis is an inflammation of the tonsils, which are lymph nodes at the back of the throat. They are responsible for protecting the body from infection, especially those caused by Streptococcus bacteria.

Symptoms: Tonsillitis caused by S. pyogenes bacteria leads to sore throat, difficulty swallowing, loss of appetite and fever. Some patients may notice white spots in the throat, which is usually a sign of a bacterial tonsil infection. 

Treatment: Bacterial tonsillitis should be treated with antibiotics as prescribed by a doctor. Most times, penicillin or derivatives are prescribed. Salt water gargles may also be beneficial.

Surgical removal of the tonsils, or tonsillectomy, is only recommended for chronic, repetitive cases of tonsil inflammation or infection. 

3. Impetigo

Impetigo is a skin infection that is caused by bacteria naturally found on the skin and along the respiratory tract (like Streptococcus pyogenes, for example). Children with signs of impetigo should stay home and avoid crowded places to prevent transmission to others. 

Symptoms: Signs of impetigo usually emerge when the immune system is weakened, which is an ideal time for bacteria to multiply and spread. Symptoms include small clusters of skin bumps, usually on the face, which can rupture and leave red marks or crust on the wound. 

Treatment: Treatment is directed by a doctor and usually involves the use of a topical antibiotic on the wounds 3 to 4 times per day. It is important to follow treatment as prescribed to avoid spreading of the bacteria to the bloodstream and other organs.

4. Erysipela

Erysipela is an infectious disease caused by Strep A bacteria. It is most frequent in people over 50, those who are overweight and diabetics. Erysipela is treatable if treatment is initiated quickly by a family doctor or dermatologist.

Symptoms: Erysipela is characterized by the appearance of red wounds on the face, arms or legs. These wounds are very painful, and if left untreated, they may start to build-up with pus or necrotic tissue. These wounds are great breeding grounds for S. pyogenes and other bacteria. 

Treatment: Erysipela treatment should be directed by a family doctor or dermatologist, and usually involves the use of antibiotics like penicillin. 

5. Rheumatic fever

Rheumatic fever is an auto-immune disease that can occur as a result of a Strep A infection. With this condition, antibodies that the body produces to fight this bacteria actually start to attack other healthy body tissues, causing inflammation in various areas of the body. 

Symptoms: The main symptoms of rheumatic fever are joint fever, muscular weakness, involuntary movements and arrhythmias. 

Treatment: Untreated pharyngitis or tonsillitis caused by Strep A bacteria can lead to spreading of the bacteria, which can cause rheumatic fever. Therefore, it is important for bacterial infections to be adequately treated to prevent further complications. 

In confirmed cases of rheumatic fever, the dermatologist, family doctor or cardiologist may recommend antibiotics and medications to relieve symptoms, like ibuprofen and prednisone. In addition, it is important to drink plenty of fluids during treatment and to maintain a balanced diet in order to recover quickly. 

6. Necrotizing fasciitis

Necrotizing fasciitis is a rare, extensive and quick-spreading infection that is characterized by bacteria entering the body through a wound. The bacteria, usually Staphylococcus aureus or Streptococcus pyogenes, multiplies quickly and lead to necrosis of the wound and tissue surrounding it. 

Symptoms: The main symptoms are high-grade fever, intense and localized pain, blisters, excessive fatigue and worsening appearance of the wound. 

Treatment: Wounds that take a long time to heal or appear to be getting worse over time should be assessed by a doctor to confirm or rule out necrotizing fasciitis. Usually, the doctor will prescribe IV antibiotics to eradicate bacteria quickly and prevent further complications. In some cases, affected tissue may need to be surgically removed to prevent further spreading. 

7. Toxic shock syndrome

Toxic shock syndrome (TSS) is characterized by the presence of bacteria in the bloodstream that can lead to gradual organ failure. It is usually caused by Staphylococcus aureus bacteria, however, there has been a rise in cases of TSS caused by Strep A bacteria.

TSS caused by Strep A bacteria is diagnosed through a blood culture test which assesses for the presence of bacteria in the blood. The doctor will also investigate for signs of this condition,  like low blood pressure, kidney disease, clotting problems, liver disease and necrosis of the tissue. 

Symptoms: The initial symptoms of TSS are fever, red rashes and hypotension. If the infection is left untreated, it may lead to multiple organ failure and death, 

Tretament: You are advised to see a doctor urgently if you suspect you have toxic shock syndrome, so that treatment is initiated immediately to prevent organ failure. 

Confirming a diagnosis

Strep A diagnosis is confirmed by a doctor according to the presenting symptoms and lab test results. One test that is used to confirm Strep A is Antistreptolysin O Titers, which are antibodies produced by the body to attack Strep A bacteria. 

This test is usually done while fasting for 4 to 8 hours, although these recommendations can vary from lab to lab.