Strep throat is usually accompanied by a fever, but not always. Other signs of strep throat include swollen lymph nodes and white patches on your tonsils.

If you have a sore, scratchy throat that lasts longer than a couple of days, you could have a bacterial infection known as a strep throat.

While viruses (according to the Centers for Disease Control and Prevention) are the cause of most sore throats, strep throat is bacterial. It’s caused by Streptococcus pyogenes (group A Streptococcus) and is highly contagious.

Your doctor will most likely diagnose strep throat with a swab sample. For most people, a swab sample is not painful, but it could make you gag.

Treatment for strep throat commonly includes an antibiotic.

Yes, you can have strep throat without having a fever.

Doctors will commonly look for five primary signs in the first stage of diagnosing strep throat:

  1. No Cough. If you have a sore throat, but aren’t coughing, it could be a sign of strep.
  2. Swollen lymph nodes. If the lymph nodes (sometimes wrongly referred to as glands) in the front part of your neck are swollen, it could be a sign of strep.
  3. White spots on tonsils. If you look in your mouth (with your tongue pushed down) and see white spots on your tonsils, it could be a sign of strep.
  4. Petechiae. If petechiae (tiny, red spots) are visible on the roof of your mouth, it could be a sign of strep.
  5. Fever. If you’re running a fever, it could be a sign of strep.

The more of these symptoms you have, the greater the chance you have strep throat. However, you could have all of these symptoms and not have strep throat. You could also have just one or two of these symptoms and have strep throat. The only way to be sure is by testing a sample from your throat.

If your doctor suspects strep throat, they’ll most likely order one or both of two tests: a rapid antigen test and a throat culture.

  • Rapid antigen test. The doctor will use a long swab to collect a sample from your throat and look at it for antigen (substance from the bacterium that stimulates an immune response). This test takes minutes, but even if the test is negative, you doctor might still want a throat culture. If the test is positive, your doctor will probably prescribe an oral antibiotic.
  • Throat culture. Using a long swab, the doctor will collect a sample of secretions from your tonsils and the back of your throat. This sample will be cultured in a laboratory to see if the bacterium is present and grows. For this reason, it can take two days to get the results of a throat culture.

If you have strep throat, you’re contagious whether or not you’re showing symptoms, such as fever.

If your doctor has prescribed antibiotics, you should start feeling better in a day or two. In most cases, according to the Mayo Clinic, you’ll no longer be contagious 24 hours after beginning treatment.

Just because you’re feeling better (and are most likely not contagious) in a relatively short period of time, does not mean that you can stop taking all of the medicine prescribed by your doctor.

According the U.S. Food & Drug Administration (FDA), stopping an antibiotic treatment early might result in not all the bacteria being killed. Furthermore, there’s a likelihood that the remaining bacteria might become resistant to the antibiotic.

Even if you’re not displaying all the common symptoms — such as fever — of the bacterial infection known as strep throat, you may still have it and be contagious.

Although certain symptoms are a strong indication, the only way for you to be absolutely sure that you have strep is by a doctor swabbing your throat and rapid testing for Streptococcal antigen, or running a throat culture.