What is strep throat?
Strep throat is an infection of the throat caused by bacteria called streptococci. Most sore throats are caused by viruses, but some are caused by streptococci. There are different types of streptococci. The type that causes serious sore throats and needs to be treated with antibiotics is a Group A streptococcus.
Strep throat infections are very contagious. They are usually passed directly from person to person.
Strep throat is common in school-age children. Children under 2 years old and adults not exposed to children are much less likely to get strep throat.
Strep throat symptoms
The symptoms of a strep throat infection may include:
- sore, red throat
- painful swallowing
- muscle aches and pains
- feeling tired
- swollen, tender lymph nodes ("glands") in the neck
- loss of appetite.
Strep throat diagnosis
Your doctor will ask about your symptoms and examine your throat. They may rub a cotton swab against a tonsil in the back of your throat to get a sample of bacteria.
The sample will be tested in a lab to see if the cause of the sore throat is bacteria or a viral infection.
Strep throat treatment
If your doctor suspects you have strep throat, they may prescribe an antibiotic before you have all the results from the lab tests. It is very important to take all of the prescribed medicine, even after the symptoms have gone away, to prevent the infection from coming back.
The symptoms of strep throat may go away as soon as 24 hours after you start treatment. The symptoms rarely last longer than 5 days.
You can be contagious for 2 to 3 weeks if you’re not treated. But if you take antibiotics, you will stop being contagious after about 24 hours.
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Last reviewed: December 2017