Pharyngitis

Pharyngitis is inflammation of the throat, which causes a sore throat. It is one of the most common reasons for a doctor visit. Most cases are caused by viruses, such as cold viruses, influenza, COVID-19 and Epstein-Barr virus (mono), and clear within a week without antibiotics. The most important bacterial cause is group A streptococcus (strep throat), which is most common in children aged 5 to 15. Signs that point more to strep include fever, swollen tender glands in the front of the neck, pus on the tonsils, and the absence of a cough or runny nose.

Lab tests linked to pharyngitis:

• Mixed respiratory flora: a throat culture result showing normal bacteria that live in the throat, with no specific disease-causing germ identified.
• Doctors use a rapid strep test or throat culture to check for group A strep. They may add tests for COVID-19, influenza, mono (a monospot or EBV antibody test), or gonorrhea in some situations.

How results are read:

• A positive rapid strep test confirms strep throat. In children and teens, a negative rapid test is usually confirmed with a throat culture.
• Mixed respiratory flora with no group A strep suggests the sore throat is not caused by strep. Viral causes don't grow on routine throat culture.
• Clinical scoring tools help decide who needs testing. Adults with low scores often don't need a strep test.

When to see a doctor:

• See a doctor about a sore throat with fever and swollen neck glands, or one that lasts more than a week.
• Get urgent care for severe pain on one side of the throat, difficulty opening the mouth, or a muffled voice.
• Call your emergency number for difficulty breathing, drooling, or being unable to swallow fluids.

Clinical takeaway: pharyngitis is usually viral, and a rapid strep test or throat culture is used to find strep throat, the main cause that needs antibiotics.