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What are streptococcal infections?

A streptococcal, or strep, infection is caused by bacteria and can be mild to severe.


Symptoms of streptococcal infections vary widely because there are many types of infections but some symptoms include:

  • Sore throat
  • Red skin rash
  • Severe pain and swelling, often rapidly increasing
  • Fever and chills
  • Redness at a wound site
  • Sudden onset of generalized or localized severe pain, often in an arm or leg
  • Dizziness and confusion
  • Flu-like symptoms such as fever, chills, muscle aches, nausea and vomiting

Symptoms of strep infections in newborns may include:

  • Fever
  • Difficulty feeding
  • Irritability
  • Difficulty breathing
  • Bluish color to skin
  • Difficulty waking up the baby

How is it diagnosed?

Because bacteria cause strep infections, a culture can confirm a diagnosis. Different types of cultures are used for different symptoms and infections, including:

  • Blood culture
  • Lumbar puncture to test fluid near the spinal cord (cerebrospinal fluid) for strep bacteria
  • Urine test
  • Throat swab 


The two types of strep bacteria are Group A and Group B.

Group A strep can cause infections including:

  • Impetigo: a mild skin infection
  • Strep throat: a sore throat often with white spots on the tonsils
  • Scarlet fever: a complication of strep throat that causes a red skin rash
  • Toxic shock syndrome: an invasive strep infection that causes a rapid drop in blood pressure and organ failure in the kidneys, liver or lungs
  • Necrotizing fasciitis: an invasive strep infection also called "flesh-eating bacteria" that destroys muscle, fat and skin tissue

Group B strep mainly affects newborns (but can also affect adults) with infections such as:

  • Blood infections
  • Pneumonia
  • Bacterial meningitis
  • Skin infections (in adults)
  • Urinary tract infections (in adults)
  • Bone and joint infections (in adults)
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