A sore throat, also called a throat infection or pharyngitis, is a painful inflammation of the back part of the throat (pharynx). Pharyngitis can involve some or all of these parts of the throat:
- The back third of the tongue
- The soft palate (roof of the mouth)
- The tonsils (fleshy tissue that are part of the throat's immune defenses).
The most common cause of sore throat is infection with bacteria or a virus.
Because an infection of the pharynx almost always involves the tonsils, tonsillitis (inflammation of the tonsils) was once a common name for infectious pharyngitis.
About 90% of throat infections are caused by a virus. Although people who have the flu (influenza), cold sores (oral herpes simplex) or infectious mononucleosis ("mono") also commonly have a sore throat, these viral infections usually cause other telltale symptoms in addition to throat pain.
In regions that have warm summers and cool winters, viral pharyngitis typically peaks during the winter and early spring. This is a time when people are more likely to gather in poorly ventilated rooms. The viruses that cause pharyngitis spread easily.
The viruses can spread through the air by hanging on to droplets from coughs and sneezes. They stick to unwashed hands that have been exposed to fluids from a sick person's nose or mouth.
In most people who are otherwise healthy, simple viral pharyngitis doesn't last long, goes away on its own and does not causes any long-term complications, although the short-term discomfort can be significant.
In cases of infectious pharyngitis that are not viral, the cause is almost always a bacterium -- usually a group A beta-hemolytic Streptococcus, which causes what is commonly called strep throat. Like viral pharyngitis, strep throat can spread quickly and easily within a community, especially during late winter and early spring.
Unlike most forms of viral pharyngitis, however, untreated strep throat can lead to serious complications, such as glomerulonephritis (a kidney disorder) and rheumatic fever (a potentially serious illness that can damage heart valves). A strep infection also has the potential to spread within the body, causing pockets of pus (abscesses) in the tonsils and in the soft tissue around the throat.
The main symptom of pharyngitis is a sore throat and pain with swallowing. In infectious pharyngitis, other symptoms vary depending on whether the infection is viral or bacterial (usually strep throat):
- Viral pharyngitis -- Sore throat often is accompanied by other symptoms, such as:
- A red throat
- Runny or stuffy nose
- Dry cough
- Redness of the eyes
Children may have diarrhea.
Some viruses cause painful sores in and around the mouth, including the lips.
- Strep throat -- Strep throat and other forms of bacterial pharyngitis cause sore throat, pain with swallowing and a red throat. These symptoms tend to be more severe with Strep throat compared to viral pharyngitis. Other symptoms that often occur with Strep throat include:
- Body ache and a general sick feeling generally sick feeling
- Enlarged tonsils with white spots
- Swollen, tender lymph nodes (swollen glands) in the front of the neck.
Children also can have nausea, vomiting and abdominal pain.
Because symptoms of viral and bacterial pharyngitis can overlap, it may be difficult for the doctor to distinguish between 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, an infection with fungi (Candida or "yeast") sometimes can cause throat pain, difficulty swallowing and white patches inside the mouth. This throat infection, commonly called thrush, usually affects infants and people with weakened immune systems.
A sore throat that lasts for more than a couple of weeks may be caused by acid reflux from the stomach, breathing through the mouth in a dry environment, postnasal drip or, rarely, a tumor.
After reviewing your symptoms, the doctor will ask if you might recently have been exposed to someone with strep throat or any other infection involving 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 quite sure that you have strep throat, he or she may prescribe antibiotics without further testing. If there is some uncertainty, the doctor may want to do a strep test.
A rapid strep test is done in your doctor's office, takes only a few minutes to do and detects 80% to 90% of all cases of strep throat. If this quick test is negative, but your doctor still believes you might have strep, your doctor will take a sample of your throat fluids for more intensive testing in a laboratory. Results will be available in 24 to 48 hours.
If you have simple viral pharyngitis, your symptoms should go away gradually over a period of about one week. If you have strep throat, your symptoms should subside within two to three days after you begin taking antibiotics.
While it's impossible to prevent all infections, you can help to decrease exposure and spreading:
- Wash your hands frequently, especially after blowing your nose or after caring for a child with a sore throat.
- If someone in your home has pharyngitis, keep his or her eating utensils and drinking glasses separate from those of other family members. Wash these objects thoroughly in hot, soapy water.
- If a toddler with pharyngitis has been chewing or sucking on toys, wash these objects thoroughly in water and disinfectant soap, then rinse well.
- Promptly dispose of any dirty tissues from runny noses and sneezes, and then wash your hands.
- Do not allow a child who has been diagnosed with strep throat to return to school or day care until he or she has been taking antibiotics for at least 24 hours and symptoms have improved.
Because antibiotics do not work against viruses, viral pharyngitis usually is treated by treating the symptoms to make you feel more comfortable until your body's immune system defeats the infection. These measures include:
- Getting plenty of rest (either in or out of bed)
- Taking ibuprofen (Advil, Motrin), acetaminophen (Tylenol) or aspirin (in adults only) to relieve throat pain
- Drinking plenty of water to prevent dehydration
- Gargling with warm salty water to ease throat pain
- Drinking warm liquids (tea or broth) or cool liquids or eating gelatin desserts or flavored ices to soothe the throat
- Using a cool mist vaporizer to relieve throat dryness
- Using nonprescription throat lozenges or anesthetic throat sprays
These measures will help to ease your discomfort with any type of throat infection. If you have strep throat, you also will take antibiotics to prevent complications. Your doctor will prescribe a 10-day course of penicillin or amoxicillin to eliminate the strep bacteria. If you are allergic to penicillin, including amoxicillin, you may be given erythromycin (sold under several brand names) or one of the other macrolides, such as azithromycin (Zithromax). It's important to take all the medication, even after you start to feel better.
Call your doctor promptly if you have a sore throat along with any of the following symptoms:
- Painful swallowing that prevents you from drinking water or other clear fluids
- Difficulty breathing through your mouth
- Noisy breathing or excessive drooling
- Fever above 101 degrees Fahrenheit
Also, call your doctor if you have any type of throat discomfort that lasts for more than two weeks.
Overall, the prognosis is excellent. Almost all people with viral and strep pharyngitis recover completely without complications.
National Institute of Allergy and Infectious Diseases (NIAID)
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Bethesda, MD 20892-6612
National Center for Infectious Diseases
Centers for Disease Control and Prevention
1600 Clifton Road, NE
Atlanta, GA 30333
American Academy of Pediatrics (AAP)
141 Northwest Point Blvd.
Elk Grove Village, IL 60007-1098
American Academy of Otolaryngology -- Head and Neck Surgery
One Prince St.
Alexandria, VA 22314-3357