Strep throat is a bacterial infection caused by bacteria called group A Streptococcus (group A strep), and is a common cause of sore throat. Antibiotics such as penicillin or amoxicillin are often used to treat strep throat.
Symptoms of strep throat often come on quickly and may include:
- Sore throat
- Pain when swallowing
- Fever
- Red throat
- White patches or streaks of pus on the tonsils, back of the throat, and tongue
- Tiny, red spots on the roof of the mouth
- Swollen lymph nodes in the front of the neck
- Swollen tonsils
- Swollen uvula
- Whitish, furry film on the tongue
- Headache
- Stomach pain
- Nausea
- Vomiting
- Rash (scarlet fever)
What Causes Strep Throat?
Strep throat is caused by bacteria called group A Streptococcus (group A strep).
Group A strep lives in the nose and throat and can be contagious. When a person infected with strep coughs or sneezes, they release respiratory droplets with the bacteria into the air.
Strep can be transmitted when people:
- Inhale the respiratory droplets
- Touch something with droplets on it and then touch their mouth or nose
- Share glasses, plates, or utensils with an infected person
- Touch sores on the skin caused by group A strep (impetigo)
- Eat improperly handled food (rare)
How Is Strep Throat Diagnosed?
Strep throat is diagnosed with:
- A rapid strep test
- A swab is taken of the throat
- Results are usually available in about 15 minutes
- Throat culture
- A throat culture swab can take 2-3 days to yield results but is more accurate than a rapid strep test
What Is the Treatment for Strep Throat?
Antibiotics are used to treat strep throat.
- Penicillin or amoxicillin are the first-line choices
- Other antibiotics may be used for people allergic to penicillin
- If antibiotics are prescribed, take the entire dose as prescribed even if you feel better before you have finished all the medication
If a person tests positive for strep throat but has no symptoms (is a “carrier”) treatment is often not needed.
How Do You Prevent Strep Throat?
Recurrent infections with strep throat can happen. The illness may be prevented in some cases by:
- Washing hands frequently with soap and warm water for at least 20 seconds
- Using an alcohol-based hand sanitizer when soap and water are not available
- Covering the mouth and nose when coughing or sneezing
- Coughing or sneezing into a tissue or upper arm or elbow, not the hands, if a tissue is not available (discard used tissues immediately)
- Washing glasses, utensils, and plates thoroughly after someone who is infected uses them
- If you have strep throat:
- Stay home from work or school until you no longer have a fever and you have taken antibiotics for at least 24 hours
- Take the full course of antibiotics exactly as prescribed
From 
https://www.cdc.gov/groupastrep/diseases-public/strep-throat.html