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Sore Throat: Is It Strep or Viral?

Although many people assume that a sore throat means strep throat, most sore throats are not strep. Only about 15 percent of all sore throats are actually caused by strep. 

Strep throats are caused by bacteria—one of about 80 strains of group A streptococcal bacteria. Most sore throats are caused by viruses. Strep throats are usually not associated with a cough or runny nose. Viral sore throats, on the other hand, often are accompanied by a cough, runny nose, or congestion. Doctors treat group A strep with antibiotics. Viral infections do not respond to antibiotics.

Strep is more common in school-age children than in infants, the American Academy of Pediatrics (AAP) says. It's common where people are in close quarters, and it's more common in the winter when we're crowded together indoors.

Test needed

Although the symptoms of strep and viral sore throats are similar, your health care provider can't make an accurate diagnosis without a test. The test used is either a rapid strep screen done in the doctor's office or a throat culture done in a lab.

A pediatrician who suspects strep will probably do a rapid test for strep, according to the AAP, because the results are available in 10 or 15 minutes.

Though quite accurate, the rapid test sometimes yields "false negatives" when strep is actually there. If the test is negative but other symptoms exist, your doctor may swab the infected area to do a culture for the suspected bacteria. Culture results take 24 to 48 hours.


If left untreated, strep can affect other parts of a child's body, including the heart valves, lungs, kidneys, and ears. Major complications of a strep infection include scarlet fever, Sydenham's chorea, rheumatic fever, acute glomerulonephritis, pneumonia, septicemia, meningitis, and necrotizing fasciitis. Minor complications include otitis media and impetigo. These complications can last weeks, months, or even a lifetime.

This is why it's so important to keep children on an antibiotic for the entire prescribed length of time, even if they're feeling better, the AAP says.

Signs of strep throat

  • Sore throat

  • Difficulty swallowing

  • Fever, usually 101 degrees or higher

  • A rough, red skin rash, but not in all cases

  • Swollen glands in the neck

  • Swelling of tonsils, possibly with pus or bleeding spots

  • Headache

  • Abdominal pain and/or nausea