Pharyngitis: Definition, Causes, Symptoms, Diagnosis, Treatment, Prognosis and Prevention

Also called a throat infection, it is a painful swelling of the back of the throat (pharynx).

Pharyngitis can affect some or all of these parts of the throat:

  • The posterior third of the tongue.
  • The soft palate (roof of the mouth).
  • The tonsils (fleshy tissue that is part of the immune defenses of the throat).

Causes of pharyngitis

The most common causes of a sore throat are infection with bacteria or a virus.

Because infection of the pharynx almost always involves the tonsils, tonsillitis (inflammation of the tonsils) was once a common name for infectious pharyngitis.

A virus causes about 90 percent of throat infections.

Although people who have the flu, cold sores (oral herpes simplex), or infectious mononucleosis often have a sore throat, these viral infections usually cause other tell-tale symptoms and a sore throat.

In regions that have hot summers and cold winters, viral pharyngitis usually peaks during winter and early spring. This is when people are most likely to gather in stuffy rooms.


Viruses that cause pharyngitis spread quickly.

Viruses can spread through the air by hanging on droplets from coughs and sneezes. They stick to dirty hands that have been exposed to fluids from a sick person’s nose or mouth.

In most otherwise healthy people, uncomplicated viral pharyngitis does not last long, clears up on its own, and does not cause long-term complications, although short-term discomfort can be significant.

In cases of infectious pharyngitis that are not viral, the cause is almost always a bacterium, usually group A beta-hemolytic streptococcus, which causes what is commonly known as strep throat.

Like viral pharyngitis, strep throat can spread quickly and easily within a community, especially in late winter and early spring.

However, unlike most forms of viral pharyngitis, untreated strep throat can lead to severe complications, such as glomerulonephritis (a kidney disorder) and rheumatic fever (a potentially serious condition that can damage the heart valves).

A strep infection also can spread within the body, causing pockets of pus (abscesses) on the tonsils and in the soft tissue around the throat.

Symptoms of pharyngitis

The main symptom of pharyngitis is a sore throat and pain when swallowing. In infectious pharyngitis, other symptoms vary depending on whether the infection is viral or bacterial (usually strep throat):

Viral pharyngitis – Other symptoms, such as: often accompany a sore throat

  • A red throat.
  • Stuffy nose
  • Dry cough.
  • Conquer.
  • Redness of the eyes.
  • Diarrhea (children can present it in some cases).

Some viruses cause painful sores in and around the mouth, including the lips.

Strep throat: Strep throat and other bacterial pharyngitis cause a sore throat, pain when swallowing, and a red throat. These symptoms tend to be more severe with strep throat than viral pharyngitis.

Other symptoms that often appear with strep throat include:

  • Fever.
  • Pain in the body and a feeling of discomfort in general.
  • Headache.
  • Enlarged tonsils with white spots.
  • Swollen and tender lymph nodes (swollen glands) in the front of the neck.
  • Children may also have nausea, vomiting, and abdominal pain.

Because the viral and bacterial pharyngitis symptoms can overlap, it can be difficult for the doctor to distinguish them based on symptoms alone.

As a general rule, if you have a prominent cough and nasal symptoms, you are more likely to have viral pharyngitis than strep throat.

In addition to viral and bacterial pharyngitis, a fungal infection (Candida or “yeast”) can sometimes cause a sore throat, difficulty swallowing, and white patches inside the mouth.

This throat infection, commonly called thrush, usually affects babies and people with weakened immune systems.

A sore throat that lasts more than a couple of weeks can be caused by acid reflux from the stomach, breathing through the mouth in a dry environment, postnasal drip, or, rarely, a tumor.

When to call a professional

Call or see a doctor right away if you have a sore throat along with any of the following symptoms:

  • Painful swallowing that prevents you from drinking water or other clear liquids.
  • Difficulty breathing through the mouth.
  • Noisy breathing or excessive drooling.
  • Fever above 101 degrees Fahrenheit.

Also, call your doctor if you have any throat discomfort that lasts longer than two weeks.

Diagnosis of pharyngitis

After reviewing your symptoms, the doctor will ask if you may have recently been exposed to strep throat or any other infection that affects the throat, nose, or ears.

After recording your temperature, your doctor will examine you, paying particular attention to your mouth, throat, nose, ears, and the lymph nodes in your neck. If your doctor is sure you have strep throat, they may prescribe antibiotics without further testing.

If there is any uncertainty, your doctor may want to have a strep test.

A rapid strep test is done in your doctor’s office, takes just a few minutes, and detects 80% to 90% of all strep throat cases.

If this rapid test is negative, but your doctor still thinks you might have strep, they will take a sample of your throat fluids for more intensive testing in a lab.

Results will be available in 24 to 48 hours.

Expected duration

If you have uncomplicated viral pharyngitis, your symptoms will gradually disappear over about a week. If you have strep throat, your symptoms should subside within two to three days after you start taking antibiotics.


Because antibiotics don’t work against viruses, viral pharyngitis is usually treated by treating symptoms to make you more comfortable until your body’s immune system defeats the infection.

These measures include:

  • Get enough rest (in or out of bed).
  • Take ibuprofen (Advil, Motrin), acetaminophen, or aspirin (adults only) to relieve a sore throat.
  • Drink plenty of water to prevent dehydration.
  • Gargle with warm salt water to ease a sore throat.
  • Drink warm liquids (tea or broth) or cold liquids, and eat gelatin desserts or flavored ice creams to soothe the throat.
  • Use a cool-mist vaporizer to relieve a dry throat.
  • Using over-the-counter throat lozenges or numbing throat sprays.

These measures will help ease your discomfort with any throat infection. If you have strep throat, you will also take antibiotics to prevent complications.

Your doctor will prescribe a 10-day course of penicillin or amoxicillin to kill the strep bacteria.

If you are allergic to penicillin, including amoxicillin, you may be given erythromycin (sold under various brand names) or one of the other macrolides, such as azithromycin. Taking all of your medications is essential, even after feeling better.


In general, the prognosis is excellent. Most people with strep and viral pharyngitis make a full recovery without complications.


While it is impossible to prevent all infections, you can help decrease exposure and spread:

  • Wash your hands often, especially after blowing your nose or caring for a child with a sore throat.
  • If someone in your home has pharyngitis, keep their kitchen utensils and glasses separate from other family members. Wash these items thoroughly in hot, soapy water.
  • If a young child with pharyngitis has been chewing or sucking on toys, wash these objects well with disinfectant soap and water, then rinse well.
  • Promptly dispose of dirty tissues from nasal mucus and sneezes, and then wash your hands.
  • Please do not allow a child diagnosed with strep to return to school or daycare until they take antibiotics for at least 24 hours and improve symptoms.