Strep throat is a bacterial infection that can easily spread to other people. Children and some adults are more likely to get strep throat than others. It is usually a mild infection, but serious complications can occur. There is a quick test doctors can use to see if you have strep throat. If the test is positive, your doctor can prescribe antibiotics so that you feel better sooner and protect others from getting sick.
Most sore throats are caused by viruses, but strep throat is caused by bacteria called group A Streptococcus or group A strep.
Group A strep live in the nose and throat and can easily spread to other people. When someone who is infected coughs or sneezes, the bacteria travel in small droplets of water called respiratory droplets. You can get sick if you breathe in those droplets or if you touch something that has the droplets on it and then touch your mouth or nose. You could also become ill if you drink from the same glass or eat from the same plate as a sick person. It is possible to get strep throat from touching sores on the skin caused by group A strep (impetigo).
Although rare, group A strep can be spread through food if it is not handled properly (visit CDC's food safety page). Pets or household items, like toys, are not known to spread these bacteria.
In general, strep throat is a mild infection, but it can be very painful. Symptoms of strep throat usually include:
- Sore throat that can start very quickly
- Pain when swallowing
- Red and swollen tonsils, sometimes with white patches or streaks of pus
- Tiny, red spots (petechiae) on the roof of the mouth (the soft or hard palate)
- Swollen lymph nodes in the front of the neck
Other symptoms may include a headache, stomach pain, nausea, or vomiting — especially in children. Cough, runny nose, hoarseness (changes in your voice that makes it sound breathy, raspy, or strained), and conjunctivitis (also called pink eye) are not symptoms of strep throat and suggest that a virus is the cause of the illness. Someone with strep throat may also have a rash known as scarlet fever (also called scarlatina).
It usually takes two to five days for someone exposed to group A strep to become ill.
Strep Throat: More Common in Children
- Between 4 and 6 out of every 20 children with a sore throat have strep throat
- Only 1 to 3 out of every 20 adults with a sore throat have strep throat
Anyone can get strep throat, but there are some factors that can increase your risk of getting this common infection.
Strep throat is more common in children than adults. It is most common in children 5 through 15 years old. It is rare in children younger than 3 years old. Parents of school-aged children and adults who are often in contact with children will have a higher risk for strep throat than adults who are not around children very often.
Close contact with another person with strep throat is the most common risk factor for illness. For example, if someone has strep throat, it often spreads to other people in their household.
Infectious illnesses tend to spread wherever large groups of people gather together. Crowded conditions — such as those in schools, daycare centers, or military training facilities — can increase the risk of getting a group A strep infection.
Since sore throats can be caused by many viruses and bacteria, it is very important to determine if group A strep is the cause. A rapid strep test or a throat culture is needed. A doctor cannot tell if you have strep throat just by looking at the throat.
A rapid strep test involves swabbing the throat and running a test on the swab to quickly see if group A strep is causing the illness. If the test is positive, doctors can prescribe antibiotics (medicine that kills bacteria in the body). If the rapid strep test is negative, but a doctor still strongly suspects strep throat, then they can take a throat culture swab to see if bacteria grow from the sample. A culture test requires more time to get the results but can be important to use in children and teens because they are at risk of getting rheumatic fever if their strep throat infection is not treated. For adults, it is usually not necessary to do a throat culture following a negative rapid strep test since there is little risk of adults getting rheumatic fever following a strep throat infection.
Unlike sore throats caused by viruses, strep throat is treated with antibiotics. Either penicillin or amoxicillin are recommended as a first choice for people who are not allergic to penicillin, but other antibiotics can be used to treat strep throat in people who are allergic to penicillin (learn more about sore throats and antibiotic use). Antibiotics help shorten how long someone is sick, prevent spreading the disease to others, and prevent getting complications like rheumatic fever.
Someone who has no symptoms but tests positive for strep throat is known as a "carrier." Carriers usually do not need antibiotics. They are less likely to spread the bacteria to others and very unlikely to get complications. If a carrier gets a sore throat illness caused by a virus, the rapid strep test can be positive even though the illness is not caused by the bacteria that cause strep throat. If someone keeps getting a sore throat after testing positive for strep throat and being treated with the right antibiotics, this may be a clue that the person is a strep carrier. Talk to your healthcare professional if you think you or your child may be a strep carrier.
Complications can occur after a strep throat infection. This can happen if the bacteria spread to other parts of the body. Complications can include abscesses (pockets of pus) around the tonsils, swollen lymph nodes in the neck, and sinus or ear infections. Other complications can affect the heart (rheumatic fever) or kidneys (post-streptococcal glomerulonephritis).
People can get strep throat more than once, so having the infection does not protect you from getting it again in the future. While there is no vaccine to prevent strep throat, there are things you can do to protect yourself and others.
The best way to keep from getting or spreading strep throat is to wash your hands often, especially after coughing or sneezing and before preparing foods or eating. To practice good hygiene you should:
- Cover your mouth and nose with a tissue when you cough or sneeze
- Put your used tissue in the waste basket
- Cough or sneeze into your upper sleeve or elbow, not your hands, if you don't have a tissue
- Wash your hands often with soap and water for at least 20 seconds
- Use an alcohol-based hand rub if soap and water are not available
You should also wash glasses, utensils, and plates after someone who is sick uses them. After they have been washed, these items are safe for others to use.
Someone with strep throat is usually not able to spread the bacteria to others after they have taken the correct antibiotic for 24 hours or longer. If you are diagnosed with strep throat, you should stay home from work, school, or daycare until you no longer have a fever and have taken antibiotics for at least 24 hours so you don’t spread the infection to others.
- Page last reviewed: September 16, 2016
- Page last updated: September 16, 2016
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