Key Points
- Strep throat is a bacterial infection of the throat and tonsils caused by group A Streptococcus (GAS).
- It commonly causes a sudden sore throat and fever and differs from viral sore throats.
- Testing is required to confirm strep throat.
- Antibiotics reduce contagiousness, help people feel better sooner, and lower the risk of complications.
- Untreated strep throat can lead to serious complications, some of which may appear weeks later.
What Is Strep Throat?
Strep throat (streptococcal pharyngitis) is an infection that affects the throat and tonsils. The bacteria cause inflammation, leading to pain, redness, and swelling. Because viral infections can cause similar symptoms, testing is required to confirm strep throat.
Causes
- Strep throat is caused by group A Streptococcus bacteria.
- It is not caused by viruses.
- Other factors such as allergies or irritants may cause sore throat symptoms, but they do not cause strep throat itself.
How Strep Throat Spreads
Strep throat spreads easily from person to person, especially in close-contact settings such as households and schools. Transmission occurs through:
- Respiratory droplets released when an infected person coughs, sneezes, talks, or breathes.
- Direct contact with droplets on hands or surfaces, followed by touching the mouth, nose, or eyes.
- Sharing items such as drinking glasses.
People can spread the infection before symptoms appear.
Is Strep Throat Contagious?
Yes. Strep throat is contagious.
- Without antibiotic treatment, a person may remain contagious for weeks.
- After starting antibiotics, most people are no longer contagious within 12–48 hours.
Symptoms of Strep Throat
Common symptoms include:
- Sudden, severe sore throat
- Pain when swallowing
- Fever
- Red and swollen tonsils, sometimes with white patches or streaks
- Swollen and tender lymph nodes in the neck
Some people may also experience headache or abdominal pain. Symptoms alone cannot confirm strep throat; testing is necessary.
Who Is at Higher Risk?
Strep throat can affect people of all ages, but it is most common in school-aged children. Risk is higher for people who:
- Live or work in close-contact environments (schools, daycares, households)
- Have frequent exposure to someone with strep throat
Diagnosis and Testing
Healthcare providers diagnose strep throat using:
- A medical history and physical exam
- A rapid strep test
- A throat culture if the rapid test is negative but suspicion remains
Testing is important because antibiotics treat bacterial infections like strep throat but do not treat viral sore throats.
Treatment
Antibiotics
Strep throat is typically treated with antibiotics prescribed by a healthcare provider. Antibiotics:
- Help people feel better sooner
- Reduce how long the infection is contagious
- Lower the risk of complications
Symptom Relief and Self-Care
In addition to antibiotics, supportive care may include:
- Drinking fluids to stay hydrated
- Rest
- Gargling with warm salt water
- Using over-the-counter pain relievers as directed
Can Strep Throat Go Away on Its Own?
Symptoms may improve over time without treatment. However, medical evaluation and antibiotic treatment are recommended because untreated strep throat can lead to serious complications.
Possible Complications
Without proper treatment, strep throat can lead to complications, including:
- Peritonsillar abscess
- Rheumatic fever
- Post-streptococcal glomerulonephritis (a kidney condition)
Some complications may develop weeks after the initial infection.
When to See a Doctor
You should contact a healthcare provider if:
- You think you may have strep throat
- Symptoms are not improving or are worsening
- You have a sore throat with fever
If you or your child has trouble swallowing fluids and cannot maintain hydration, medical evaluation is recommended.
Frequently Asked Questions
How do I know if I have strep throat?
Only a medical test can confirm strep throat. Symptoms alone are not enough.
How long is strep throat contagious?
Without antibiotics, a person may be contagious for weeks. With antibiotics, most people are no longer contagious after 12–48 hours.
Can you get strep throat without tonsils?
Yes. People without tonsils can still get strep throat, although it may occur less often.
What’s the difference between strep throat and tonsillitis?
Strep throat is caused by bacteria. Tonsillitis can be caused by viruses or bacteria and does not always involve strep infection.
When should I go to the ER for strep throat?
There is no high-quality evidence defining a universal emergency-room threshold specifically for strep throat. Seek urgent medical care if symptoms are severe or rapidly worsening.
Should I go to urgent care or see my regular doctor?
Both can evaluate and test for strep throat. There is no high-quality evidence showing one setting is always preferable over the other.
How long does strep throat last?
With antibiotics, people often start to feel better within a day or two, and most symptoms resolve within 7–10 days.
What to Do Next If You Suspect Strep Throat
If you think you may have strep throat, seek medical evaluation for testing. Prompt diagnosis and appropriate treatment can reduce symptoms, limit spread, and lower the risk of complications.
APA References List
Centers for Disease Control and Prevention. (2025, July 31). About strep throat. https://www.cdc.gov/group-a-strep/about/strep-throat.html
Centers for Disease Control and Prevention. (2025, November 18). Clinical guidance for group A streptococcal pharyngitis. https://www.cdc.gov/group-a-strep/hcp/clinical-guidance/strep-throat.html
Cleveland Clinic. (2022, December 20). Strep throat: Symptoms, causes & treatment. https://my.clevelandclinic.org/health/diseases/4602-strep-throat
Giordano, C. (2025, December 10). How long are you contagious with strep throat? GoodRx. https://www.goodrx.com/health-topic/infections/how-long-is-strep-contagious
Mayo Foundation for Medical Education and Research. (n.d.). Strep throat — Diagnosis & treatment. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/strep-throat/diagnosis-treatment/drc-20350344
National Health Service. (2024, April 8). Sore throat. https://www.nhs.uk/symptoms/sore-throat/
National Library of Medicine. (2023, July 8). Strep throat. MedlinePlus Medical Encyclopedia. https://medlineplus.gov/ency/article/000639.htm
National Library of Medicine. (2024, March 19). Strep A test. MedlinePlus Medical Test. https://medlineplus.gov/lab-tests/strep-a-test/
Shulman, S. T., Bisno, A. L., Clegg, H. W., Gerber, M. A., Kaplan, E. L., Lee, G., Martin, J. M., & Van Beneden, C. (2012). Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis: 2012 update by the Infectious Diseases Society of America. Clinical Infectious Diseases, 55(10), e86–e102. https://doi.org/10.1093/cid/cis629