Why Do I Get Strep Throat

Strep throat, also called streptococcal pharyngitis, is one of the most common illnesses you will experience at different times. It is as uncomfortable as it is very common and easily mistaken for tonsilitis.

Strep throat is caused by Streptococcus pyogenes. You can either be infected by the bacteria through your hygiene levels or contract it from an infected person. Once infected, the bacteria in the throat spreads within the throat and can lead to severe pain, difficulty swallowing, and swollen lymph nodes. 

Read on to gain more insight into what strep throat is, how you can tell when you have strep throat, and frequently asked questions that will answer some of the questions you may have.

What is strep throat?

The tonsils and throat can become infected with streptococcus bacteria. People of all ages can get strep throat, but children between the ages of 5 and 15 are most likely to get it. Usually, GAS pharyngitis develops before the age of 40 and gradually gets worse after that. Streptococcus bacterium is the most typical bacterial cause of acute pharyngitis. It accounts for between 5 and 15% of cases of sore throat in adults and between 20 and 30% in children.1,2,3,4

The following groups are at risk of strep throat:5

  • School children
  • Parents of schoolchildren
  • Adults who come in contact with schoolchildren
  • Individuals who spend time in other crowded spaces such as military training facilities and daycare centres.

Causes of strep throat

Strep throat is caused by Streptococcus pyogenes, also known as group A streptococcus (GAS). Progressive, deeper tissue-involved, and potentially fatal diseases are caused by Strep A. It causes various suppurative (pus-producing) and nonsuppurative (non-pus-producing) infections in people. Pharyngitis, pyoderma, erysipelas, cellulitis, necrotizing fasciitis, toxic streptococcal syndrome, scarlet fever, sepsis, pneumonia, and meningitis are a few of these.4

GAS causes upper respiratory infections, such as sore throat, and a medical diagnosis of tonsillitis (enlarged tonsils) or pharyngitis (inflammation of the throat), which can be brought on by streptococcus (Strep A) and other bacteria. A strep A sore throat (including tonsillitis) can develop into a more serious infection, such as a peritonsillar abscess, also known as Quincy; a collection of pus on one of the tonsils, or other invasive infections.3

Additionally, streptococcal toxic shock syndrome (STSS), a disease characterised by hypotension frequently accompanied by fever or rash with rapid progression to shock and multi-organ failure, may worsen any invasive GAS infections. Pregnant women, older individuals without children, and non-pregnant adults with underlying chronic illnesses are three populations among whom Group B streptococcus (GBS) significantly contributes to invasive infection.5

When an infected individual speaks, coughs, or sneezes, respiratory droplets are released; this is how the bacteria are transmitted. You can also contract streptococcus bacteria after touching a surface contaminated by the bacteria and then touching the nose or mouth. 

Other than bacterial infections, sore throat can also be brought on by other factors like viral infections and environmental irritants. These factors are divided into Infectious and non-infectious causes.

  • Infectious causes: Respiratory viruses (such as parainfluenza, rhinovirus, coxsackievirus, adenovirus, etc.), Acute HIV infection, Neisseria gonorrhoeae, Treponema pallidum, Epstein-Barr virus, Fusobacterium necrophorum, Mycoplasma species, Chlamydia species, Corynebacterium diphtheria, and Corynebacterium diphtheria.
  • Non-infectious causes: Allergies, second-hand smoke exposure, trauma, gastroesophageal reflux illness, autoimmune diseases (such as Behçet syndrome, Kawasaki, etc.), and foreign bodies.

Signs and symptoms of strep throat

The symptoms of a sore throat brought on by bacterial infections and viral infections differ significantly. Symptoms usually appear within 2 to 5 days after exposure to the bacteria, and they typically include:

  • Sore throat
  • Pain when swallowing
  • Swollen lymph nodes
  • Red and swollen tonsils
  • Runny nose
  • Fever
  • Headache
  • Nausea
  • Vomiting
  • Loss of appetite

It is worthy of note that some individuals may be asymptomatic and not show any signs or symptoms other than antibody response whereby there is an increase in their white blood cell levels, which try to fight the infection on their own. Being asymptomatic does not eliminate the chances of them transmitting the infection to anyone who comes in contact with them.

Management and treatment for strep throat

The majority of cases of pharyngitis will go away on their own without treatment, but in about 60% of cases, antibiotics are prescribed to prevent rare complications, such as acute rheumatic fever, rheumatic heart disease, post-streptococcal glomerulonephritis, which can damage the heart, kidney and other organs.2,4,6

Shortening the duration and intensity of a patient's symptoms, avoiding early and delayed consequences, and halting spreading the infection to others is the primary aim of treatment for GAS pharyngitis.

Strep throat is usually treated with antibiotics, such as penicillin or amoxicillin.1 After receiving antibiotics, patients may see an improvement in their symptoms within three days and may resume their regular activities after 24 hours. It is important to complete the course of antibiotics as your doctor prescribes, even when you feel better before the medication is finished. After the course of treatment, a test to determine if a person with strep throat is cured is usually not compulsory unless there is a past diagnosis of acute rheumatic fever or some other GAS complication.

While using antibiotics, it is crucial to avoid unnecessarily administering antibiotics to people who do not have high-risk GAS, as it will be counterproductive because it will result in antibiotic resistance over time, whereby antibiotics stop working for the patients due to the bacteria being able to withstand the particular type of antibiotics they receive often.6

Pain relievers, sold over-the-counter, such as acetaminophen or ibuprofen, can relieve pain and reduce fever. Drinking plenty of fluids and getting rest can also help to alleviate symptoms. 


How common is strep throat

Strep throat is a common illness that affects people of all ages, although most common in children below 16. As reported by the Centers for Disease Control and Prevention (CDC), approximately 11,000 to 13,000 cases of strep throat are reported annually in the United States.1

Is strep throat contagious?

Yes, strep throat is contagious. The bacteria is spread through respiratory droplets, released when an infected person coughs, talks, or sneezes. You can contract strep throat when you touch surfaces contaminated with these droplets or inhale them around infected persons and will begin to show symptoms about 2 to 5 days after exposure. A person with strep throat may be asymptomatic (not showing any symptoms) but still be a host for the bacteria.

What does strep throat feel like

In the pharynx, it causes a burning sensation at the back of the throat, your throat may also feel itchy, and you may have the sensation of a lump stuck in your throat. The signs and symptoms of strep throat can vary, but they typically include a sore throat, pain when swallowing, swollen lymph nodes, red and swollen tonsils, fever, headache, nausea, vomiting, and loss of appetite. 

How is strep throat diagnosed?

A throat culture of a rapid strep test is usually used for strep throat diagnoses.3 A rapid strep test can give results within a few minutes, while a throat culture can take up to a few days. When a sore throat is diagnosed solely by throat swab culturing, it is impossible to discriminate between patients with real GAS pharyngitis infections and GAS carriers with pharyngitis brought on by viral infections.

How can I prevent strep throat?

For strep throat prevention, it is important to have good hygiene practices, such as proper and frequent washing of hands, avoiding close contact with people who are sick, and covering your mouth and nose when you cough or sneeze.

When should I see a doctor?

If you have symptoms of strep throat, it is important to see a doctor as soon as possible, especially for those with recurrent strep throat or an underlying condition. Early treatment can help to prevent complications such as acute rheumatic fever (ARF) and acute post-streptococcal glomerulonephritis (a type of kidney disease caused by strep A).


Strep throat can be spread by respiratory droplets or contact with contaminated surfaces. It is more prominent during the winter and early spring months and more common among children and young people. Certain environmental factors may also make some individuals more susceptible to strep throat. 

Symptoms of strep throat include sore throat, runny nose, swollen lymph nodes, and fever. A person with strep throat may not show any symptoms, but they can still transmit it to others. It is crucial to treat your throat infection if it does not resolve within a few days and if you are susceptible to other diseases to prevent further complications. A visit to the doctor is needed when the strep throat does not resolve on its own or when it often recurs within a short time.


  1. Ashurst JV, Edgerley-Gibb L. Streptococcal Pharyngitis. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK525997/
  1. Miller, Kate M., et al. “The Global Burden of Sore Throat and Group A Streptococcus Pharyngitis: A Systematic Review and Meta-Analysis.” EClinicalMedicine, vol. 48, June 2022, p. 101458. DOI.org (Crossref). Available from:  https://doi.org/10.1016/j.eclinm.2022.101458
  1. Luo, Robert, et al. “Diagnosis and Management of Group a Streptococcal Pharyngitis in the United States, 2011–2015.” BMC Infectious Diseases, vol. 19, no. 1, Dec. 2019, p. 193. DOI.org (Crossref). Available from: https://doi.org/10.1186/s12879-019-3835-4
  1. Bennett, Julie, et al. “Risk Factors for Group A Streptococcal Pharyngitis and Skin Infections: A Case Control Study.” The Lancet Regional Health - Western Pacific, vol. 26, Sept. 2022, p. 100507. DOI.org (Crossref). Available from: https://doi.org/10.1016/j.lanwpc.2022.100507
  1. Chauhan, Smriti, et al. “Genetic Diversity among Group A Streptococcus Isolated from Throats of Healthy and Symptomatic Children.” Journal of Tropical Pediatrics, vol. 62, no. 2, Apr. 2016, pp. 152–57. DOI.org (Crossref). Available from: https://doi.org/10.1093/tropej/fmv092
  1. Parks, Tom, et al. “Invasive Streptococcal Disease: A Review for Clinicians.” British Medical Bulletin, vol. 115, no. 1, Sept. 2015, pp. 77–89. DOI.org (Crossref). Available from: https://doi.org/10.1093/bmb/ldv027
  2. Oliver, Jane, et al. “Group A Streptococcus Pharyngitis and Pharyngeal Carriage: A Meta-Analysis.” PLOS Neglected Tropical Diseases, edited by Ali M. Somily, vol. 12, no. 3, Mar. 2018, p. e0006335. DOI.org (Crossref). Available from: https://doi.org/10.1371/journal.pntd.0006335
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Chimezirim Ozonyiri

Bachelor of Science - BS, Microbiology, General, Tansian University, Nigeria

Chimezirim has several years of experience in the healthcare, non-profit, and education sectors. She is passionate about health promotion and began her journey into health and lifestyle writing over two years ago.

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