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Streptococcal sore throat (strep throat)

What is Streptococcal sore throat (strep throat)?

Streptococcal sore throat, also referred to as strep throat, is caused by the bacteria Streptococcus pyogenes (also known as Group A streptococcus). Not all sore throats are caused by streptococcal bacteria. People who are ill with a sore throat should see a health care provider to determine the cause. Strep throat is usually diagnosed by a rapid strep test or a throat culture. 

Signs and symptoms

  • Sore throat (throat appears red and there may be white pus on the tonsils)
  • Fever
  • Enlarged lymph nodes in the neck
  • Runny nose (toddlers may only have a runny nose and/or fever)
  • Headache, stomach pain, nausea, and/or vomiting
  • Red skin rash called a scarlatiniform rash, which starts on the trunk and spreads outward with a sandpaper texture
  • Children younger than 3 years with group A streptococcal infection rarely have a sore throat. Most commonly, these children have persistent nasal discharge (which may be associated with foul odor from the mouth), fever, irritability, and loss of appetite. 

Complications of strep throat can include:

  • Rheumatic fever, an inflammatory disease that can involve the heart, joints, skin, and brain. The risk of rheumatic fever is reduced by promptly treating strep throat with the appropriate antibiotics.
  • Acute glomerulonephritis, a disease of the kidneys.
  • Toxic shock syndrome.

Incubation period

2-5 days

Contagious period and spread

  • Strep throat is usually transmitted through contact with droplets and respiratory secretions from a person with infection, such as through coughing and sneezing. 
  • People are no longer contagious within 12 hours of beginning appropriate antimicrobial therapy. Infectiousness of people who are not treated gradually diminishes over a period of weeks.
  • As many as 25% of asymptomatic school children and a small number of adults carry the bacteria that cause strep throat in their nose and throat and are not ill. The risk of transmission from someone who is not sick but is carrying the virus is low.
  • Note: The bacteria that cause strep throat can also cause impetigo and scarlet fever.

Public health reporting requirements

  • Report the infection to the facility director, school nurse, or child care health consultant.
  • Individual cases of strep throat infections, scarlet fever, and rheumatic fever are not reportable to public health.
  • Suspected outbreaks of all types (including strep throat) are reportable to state or local public health. 

Control of spread

  • Family members and household contacts of an ill person do not need to be routinely tested unless they are symptomatic, or contacts are at increased risk of developing sequelae from strep infection, or the child has rheumatic fever or acute glomerulonephritis. 
  • Follow-up testing of symptomatic people with a positive strep test is not routinely recommended. If symptoms persist after antibiotic therapy, a health care provider should be consulted. 
  • Encourage frequent handwashing.

Treatment

Typically antibiotics (usually penicillin or amoxicillin) are prescribed to treat strep throat. Treatment instructions should be followed closely in order to prevent complications such as rheumatic fever.

Exclusion

  • Exclude symptomatic children and staff in child care centers and schools with strep throat until 12 hours after the first dose of antibiotic treatment. 
  • A student/child or staff member without symptoms, regardless of a positive test result, does not need to be excluded. 

Role of teachers, caregivers, and family

  • Teach children to cover their cough and avoid contact with respiratory droplets.
  • Practice and encourage good hand-hygiene techniques.