All About Strep Throat


Published: 06 March 2023

Strep throat is a bacterial infection of the throat and tonsils. The bacteria that causes strep throat is called group A Streptococcus (CDC 2023).

This same bacteria can also cause other infections, including scarlet fever and impetigo (Better Health Channel 2017).

Strep throat can affect anyone but is most common among school-aged children and teenagers between 5 and 15. Adults who are not exposed to children are unlikely to be infected, as are children younger than 3.

Strep A causes about one-third of sore throats in children but only 1 in 10 sore throats in adults (CDC 2023).

strep throat child in bed with sore throat
Strep throat is most common among school-aged children and teenagers between 5 and 15.

How is Strep Throat Transmitted?

Strep A bacteria are generally transmitted via respiratory droplets or direct contact with infected persons (Health.vic 2023). The bacteria inhabit the nose and throat and spread to others through coughing and sneezing. It is possible for someone to be infected without displaying symptoms or appearing unwell (CDC 2023).

Strep A can be spread through:

  • Breathing in respiratory droplets from coughs or sneezes
  • Touching something with respiratory droplets on it
  • Sharing drinks, plates etc. with someone who is sick
  • Touching impetigo - sores on the skin caused by strep A bacteria.

(CDC 2023; Better Health Channel 2017)

Rarely, strep throat can be caught from contaminated food items, including:

  • Milk and milk products
  • Eggs.

(Better Health Channel 2017)

Untreated individuals can be contagious for two to three weeks. However, after taking antibiotics, they are generally no longer contagious after 24 hours (Healthdirect 2020).

Risk Factors for Strep Throat

The following factors may increase the risk of Strep A infection:

  • Being a school-aged child (between 5 and 15)
  • Being a parent of a school-aged child
  • Being an adult who is often in close contact with children
  • Living in the same household as someone who has strep throat
  • Spending time in a crowded facility (e.g. schools, daycare centres).

(CDC 2023)

Symptoms of Strep Throat

Symptoms may include:

  • Sore throat that comes on quickly
  • Pain when swallowing
  • Red, swollen tonsils that may have visible white patches or streaks of pus
  • Small red spots (petechiae) on the soft or hard palate
  • Swollen, tender lymph nodes
  • Fever
  • Chills
  • Headache
  • Rash
  • Fatigue
  • Nausea or vomiting (particularly in children)
  • Body aches.

(Mayo Clinic 2022; Healthdirect 2020)

Many of these symptoms are nonspecific to strep throat and could indicate a viral infection instead. A strep throat test should be conducted to determine the cause of symptoms (Mayo Clinic 2022).

The following symptoms may indicate a virus instead of strep throat:

  • Cough
  • Runny nose
  • Hoarse voice
  • Conjunctivitis.

(CDC 2023)

Complications of Strep Throat and Related Illnesses

Scarlet Fever

Strep A infection can also cause scarlet fever, which is a pink-red body rash with a sandpaper-like texture. It is mostly seen in children (NHS 2021).

scarlet fever rash


Impetigo refers to a skin rash caused by strep A bacteria, though it can also be caused by Staphylococcus aureus (golden staph). The rash causes blisters around the nose, mouth and legs and, in severe cases, can cause fever and swollen lymph nodes. The blisters are highly contagious (Better Health Channel 2017).

Rheumatic Fever

Rheumatic fever is a possible complication of strep A infection. It’s a serious inflammatory response to the strep A bacteria that may affect the heart, joints, nervous system and skin (CDC 2023; Mayo Clinic 2022).

Rheumatic fever can cause inflamed and painful joints, a rash, fever, breathlessness, chest pain and nervous system problems (such as involuntary twitching). It can also develop into permanent heart complications such as a heart murmur or enlarged heart (Better Health Channel 2011).

Diagnosing Strep Throat

To determine whether someone has strep throat, a rapid strep test will need to be performed, as simply looking at the throat is inconclusive. The test involves a throat swab, which is then tested for strep A bacteria (CDC 2023).

If the test comes back negative but strep throat is still believed to be a possibility, a throat culture swab may be taken. This test takes more time, as it monitors the swab to see if any strep A bacteria grows, but may detect cases missed by the rapid strep test (CDC 2023).

strep test

Treating Strep Throat

Treatment for strep throat requires a course of antibiotics. After the commencement of treatment, symptoms should begin to improve within one to two days and the person should no longer be contagious after 24 hours (CDC 2023; Healthdirect 2020).

Preventing the Spread of Strep Throat

The spread of Strep A can be prevented by:

  • Regular handwashing
  • Staying away from work, school, etc. when unwell
  • Using tissues when coughing or sneezing and then disposing of them
  • Avoiding sharing crockery, cups and utensils with other people
  • Avoiding preparing food when unwell.

(Healthdirect 2020)


Test Your Knowledge

Question 1 of 3

True or false: Strep A accounts for most sore throats.


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