What is strep throat?
What causes it?
Strep throat is caused by streptococcal (strep) bacteria. There are many different types of strep bacteria. Some cause more serious illness than others. Strep throat is most often caused by group A beta-hemolytic streptococcus (GABS). Groups C and G strep bacteria also can infect the throat.
How does it spread?
Strep throat can be passed from person to person. When a person infected with strep throat breathes, coughs, or sneezes, tiny droplets with the strep bacteria go into the air and are breathed in by other people. If you come into contact with strep, it will take 2 to 5 days before symptoms start.
What are the symptoms?
The most common symptoms of strep throat are a sudden and severe sore throat, pain when you swallow, and fever. Other symptoms include swollen tonsils and lymph nodes and white or yellow spots on the back of a bright red throat. You may also have a headache and belly pain.
How is it diagnosed?
Your doctor will examine you, ask about your symptoms, and do a throat culture or rapid strep test. A rapid test gives results within about 10 minutes. But sometimes it doesn't show strep even when you have strep. A culture takes 1 or 2 days, but it's better at finding all cases of strep.
How is strep throat treated?
Strep throat is treated with antibiotics. These drugs shorten the time you're able to spread the disease, and they lower the risk of spreading the infection to other parts of your body. Antibiotics may help you feel better faster. Taking an over-the-counter medicine like acetaminophen can help relieve pain and reduce fever.
Try the following ideas to help prevent strep throat.
- Avoid contact with anyone who has a strep infection.
- Wash your hands.
Wash your hands often when you are around people with colds or viral or bacterial illnesses.
- Do not share toothbrushes or eating and drinking utensils.
- Keep up your body's resistance to infection.
Eat a good diet, get plenty of sleep, and exercise regularly. Managing stress can also strengthen your body's ability to fight off illness, such as strep throat.
- Humidify your home.
Try this during the dry winter months or year-round if you live in a dry climate. Moisture in the air (humidity) helps keep your mucous membranes moist and more resistant to bacteria. You can use a humidifier in the bedroom while you sleep. But use care if a person in the home has asthma or allergies, because mold or other particles that collect in the humidifier can make these conditions worse. Follow the directions for cleaning the machine.
- Stop smoking, and avoid breathing others' smoke.
Smoke irritates the throat tissues and may make you more likely to get an infection.
The most common symptoms of strep throat are:
- A sudden, severe sore throat without coughing, sneezing, or other cold symptoms.
- Pain when you swallow, or trouble swallowing.
- Fever over 101°F (38.3°C). Lower fevers may point to a viral infection and not strep.
- Swollen lymph nodes in the neck.
- White or yellow spots or coating on the throat and tonsils.
- Bright red throat or dark red spots on the roof of the mouth at the back near the throat.
- Swollen tonsils. But this symptom may also be caused by a viral infection.
You may also have a headache and belly pain. Less common symptoms are a red skin rash, vomiting, not feeling hungry, and body aches.
Strep can be passed from person to person. If you come into contact with the strep bacteria, it will take 2 to 5 days before you start to have symptoms.
When to Call a Doctor
Call 911 or other emergency services immediately if you:
- Have severe trouble breathing.
- Have trouble swallowing saliva.
Call your doctor now if you have:
Call a doctor if the following symptoms develop 2 to 3 weeks or longer after a strep throat infection. These symptoms may be a sign of rheumatic fever.
- Shortness of breath
- Joint pain
- Raised red rash or lumps under the skin
- Uncontrolled, jerking movements of the arms or legs
Call your doctor if your symptoms don't improve after 2 days of treatment with an antibiotic.
Watchful waiting is a good choice if your sore throat occurs with symptoms like those of a cold, such as sneezing, coughing, and a runny or stuffy nose. In general, the more of these symptoms you have, the less likely it is that your sore throat is caused by a strep infection. You can try home treatment if your sore throat isn't severe and you have other symptoms of a cold.
Check your symptoms
Exams and Tests
Your doctor will examine you, ask about your symptoms, and do a throat culture or rapid strep test.
A rapid strep test analyzes the bacteria in your throat to see if strep is causing your sore throat. The doctor uses a cotton swab to gather cells from the back of your throat for testing. This test gives results within about 10 minutes. But sometimes it doesn't show strep even when you have strep. If the rapid test is positive and says that you do have strep, there's no need to do the throat culture.
A throat culture can find strep bacteria. A culture takes 1 or 2 days, but it's better at finding all cases of strep. A sample of cells from the back of your throat is added to a substance that promotes the growth of bacteria. If no bacteria grow, the culture is negative. If strep bacteria grow, the culture is positive.
Doctors usually treat strep throat with antibiotics. These drugs shorten the time that you're able to spread the disease to others (are contagious). And they lower the risk of spreading the infection to other parts of your body. They also may help you feel better faster.
You are contagious while you still have symptoms. Most people stop being contagious 24 hours after they start antibiotics. If you don't take antibiotics, you may be contagious for 2 to 3 weeks, even if your symptoms go away.
Your doctor may also advise you to take an over-the-counter medicine like acetaminophen (such as Tylenol) or ibuprofen (such as Advil or Motrin) to help with pain and lower your fever. Be safe with medicines. Read and follow all instructions on the label. Don't give aspirin to anyone younger than 20. It has been linked to Reye syndrome, a serious illness.
Your doctor may have prescribed an antibiotic for strep throat. Take all of the antibiotic exactly as prescribed. This will help prevent the infection from coming back and will prevent complications of infection that could occur if you do not take the medicine as prescribed.
There are many ways that you can make yourself feel better while you are waiting for the strep infection to go away.
- Stay hydrated.
Drink plenty of fluids and increase humidity (moisture in the air) in your home to help keep your throat moist. Herbal teas formulated for colds may help relieve symptoms.
- Get plenty of rest.
Stay home the first day of antibiotic treatment. You are still contagious and might pass the infection to others. Rest in bed if you feel very sick. Bed rest is not required if you feel fine.
- Treat your symptoms.
- Take nonprescription medicines to relieve a painful sore throat and reduce fever. Be safe with medicines. Read and follow all instructions on the label.
- Try an over-the-counter anesthetic throat spray or throat lozenges, which may help relieve throat pain. Do not give lozenges to children younger than age 4. If your child is younger than age 2, ask your doctor if you can give your child numbing medicines.
- Protect others.
For the first 24 hours after you start taking an antibiotic, you are still contagious. You can avoid passing the strep throat infection to others and reinfecting yourself by:
- Avoiding sneezing or coughing on others.
- Washing your hands often.
- Using tissues you can throw away, not handkerchiefs.
- Using a new toothbrush as soon as you feel sick. Replace it again when you are well. You can also clean your toothbrush well before using it again. Bacteria can collect on the bristles and reinfect you.
Current as of: May 4, 2022
Author: Healthwise Staff
Kathleen Romito MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Donald R. Mintz MD - Otolaryngology