About Strep Throat

Key points

  • Strep throat is a bacterial infection in the throat and tonsils.
  • Healthcare providers can do a quick test to see if a sore throat is strep throat.
  • Antibiotics can help people with strep throat feel better faster.
A healthcare provider examining the throat of a young girl.

What it is

Strep throat is a bacterial infection in the throat and tonsils.

Worried your sore throat may be strep throat?‎

Viruses cause most sore throats. Only around 1 in 10 adults and 3 in 10 children with a sore throat have strep throat.


It usually takes 2 to 5 days after exposure to become ill with strep throat.

Common symptoms may include:

  • Fever
  • Pain when swallowing
  • Red and swollen tonsils
  • Sore throat that started very quickly and may look red
  • Swollen lymph nodes in the front of the neck
  • Tiny, red spots on the roof of the mouth, called petechiae
  • White patches or streaks of pus on the tonsils
Illustration of the inside of a healthy mouth
See what a healthy throat looks like.
A labelled illustration of the inside of the mouth of a person with strep throat
Swelling, redness, and white patches are common symptoms of strep throat.

Less common symptoms, especially for children, may include:

  • Headache
  • Nausea or vomiting
  • Rash (scarlet fever)
  • Stomach pain


Complications can occur after a strep throat infection if the bacteria spread to other parts of the body.

Complications can include:

  • Abscesses (pockets of pus) around the tonsils or in the neck
  • Ear infections
  • Post-streptococcal glomerulonephritis (a kidney disease)
  • Rheumatic fever (a disease affecting the heart, joints, brain, skin)
  • Sinus infections

Risk factors

Anyone can get strep throat, but some factors increase the risk of getting it.


Strep throat is more common in children than adults.

  • Most common: Children 5 through 15 years old
  • Rare: Children younger than 3 years old

Close contact

Close contact with another person with strep throat is the most common risk factor for illness. For example, if someone has strep throat, the bacteria often spread to other people in their household.

Contact with children: Parents of school-age children and adults who are often in contact with children are at increased risk.

Crowded settings can increase the risk of getting any group A streptococcal infection including strep throat. These settings include:

  • Daycare centers and schools
  • Detention or correctional facilities
  • Homeless shelters
  • Military training facilities


Group A Streptococcus (group A strep bacteria) cause strep throat and are contagious.


People can take steps to help protect themselves and others from group A strep infections, including strep throat.

Testing and diagnosis

Healthcare providers can use 2 types of tests to diagnose strep throat.

Treatment and recovery

Healthcare providers treat strep throat with antibiotics.

Similar conditions

Viral sore throat

The following symptoms suggest a virus, not strep throat, is the cause of a sore throat:

  • Cough
  • Runny nose
  • Hoarseness (changes in voice to sound breathy, raspy or strained)
  • Conjunctivitis (pink eye)

What's it mean to be a strep carrier?‎

Some people can test positive for group A strep bacteria but have no symptoms. Are they contagious? Do they need antibiotics?