Throat Infection

(Pharyngitis; Tonsillitis; Tonsillopharyngitis)

ByAlan G. Cheng, MD, Stanford University
Reviewed/Revised Feb 2024
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Infections of the throat and/or tonsils are common, particularly among children.

  • Throat infections are usually caused by a virus but may be caused by bacteria such as streptococcal bacteria.

  • Symptoms include severe pain when swallowing and swollen, red tonsils.

  • The diagnosis is based on an examination of the throat.

  • If untreated, throat infection that is caused by bacteria may cause an abscess to form in the tonsils.

  • Taking analgesics relieves pain; a streptococcal infection is treated with antibiotics.

  • Sometimes the tonsils have to be surgically removed.

The tonsils contain lymphoid tissue that is part of the body's immune defense system. The tonsils intercept infectious microorganisms that enter the nose and throat and sometimes cause infections of the tonsils and nearby throat tissue.

People who have had their tonsils removed can still get throat infections.

Causes of Throat Infection

Throat infections are usually caused by a virus. Most often, it is one of the viruses that cause the common cold, such as rhinovirus, adenovirus, influenza virus, or respiratory syncytial virus. Less often, another virus is involved, such as the Epstein-Barr virus (which causes mononucleosis) or human immunodeficiency virus (HIV).

In about one third of people, throat infections are caused by a bacterial infection. Group A streptococcus is the most common bacteria that causes strep throat; strep throat usually occurs in children between age 5 and age 15. Strep throat is less common among children under age 3 and older adults.

Strep throat usually resolves within 7 days, even without antibiotics. However, untreated strep throat sometimes causes complications. Complications can include tonsillar cellulitis or abscess, rheumatic fever, and kidney inflammation (glomerulonephritis).

Rarely, bacterial infections such as gonorrhea and diphtheria cause throat infections.

Symptoms of Throat Infection

People with a throat infection have severe pain when swallowing and usually speaking. The pain is sometimes also felt in the ears. Some people have fever, headache, and an upset stomach. The tonsils are red and swollen and sometimes have white patches on them. Lymph nodes in the neck may become swollen and tender.

In people who have frequent tonsil infections, the normal small pits in the tonsils sometimes become filled with white, hardened secretions that resemble tiny stones. These stones can trap odor-causing bacteria, causing chronic bad breath, and can predispose people to subsequent bouts of tonsillitis.

People with the common cold often have a runny, congested nose and a cough. People with mononucleosis often feel extremely tired and have many swollen lymph nodes, and their tonsils may swell so much that they begin to block air when a person breathes, causing noisy breathing.

Diagnosis of Throat Infection

  • A doctor's evaluation

  • Sometimes tests to check for strep throat

Doctors recognize a throat infection by viewing the throat. However, because the throat often looks the same in viral infections and bacterial infections, it is difficult for doctors to know whether the cause is a viral or bacterial infection just by looking at the throat. However, people with a runny nose and cough are more likely to have a viral infection.

Because strep throat requires antibiotics, it must be identified. To test for it, doctors swab the person's throat and do tests to identify streptococcus bacteria. Often, doctors test most children but test adults only if they meet certain criteria, such as having white patches on the tonsils (tonsillar exudates), swollen and tender lymph nodes in the neck, fever, and no cough. However, not all experts agree on when testing should be done or even when antibiotics should be given.

Treatment of Throat Infection

  • Pain relievers (analgesics)

  • For strep throat, antibiotics

  • Sometimes surgical removal of the tonsils

Drinking plenty of fluids and resting are recommended. Gargling with warm salt water has often been recommended but has not been shown to help.

Tonsillectomy

People who have repeated streptococcal infections of their tonsils may need to have their tonsils removed (tonsillectomy).

Typically, it is children who need tonsillectomy. Doctors consider tonsillectomy if the child has any of the following:

  • Repeated strep infections (6 times in 1 year, more than 4 times per year for 2 years, or more than 3 times per year for 3 years)

  • An acute infection that is severe and persistent despite being treated with antibiotics

  • Significant blockage (as may occur in obstructive sleep apnea)

  • A recurrent peritonsillar abscess

Tonsillectomy is also done if doctors suspect cancer.

For adults, doctors do not use these specific criteria for when to do tonsillectomy. However, doctors may do tonsillectomy in adults who have severe bad breath due to tonsillar stones.

For both children and adults, doctors decide whether to recommend a tonsillectomy based on individual differences (such as the person's age, general health, and the ease with which they have recovered from previous infections).

There are numerous effective techniques for tonsillectomy. The aim is to completely or partially remove the tonsils. Doctors can use a scalpel or an electrocautery device, or they can destroy the tonsils using radio waves. These techniques cause very little bleeding. Occasionally, a wire and snare technique is used. With this technique, a surgeon lassos the tonsils and snips them off with a sharp wire. All of these techniques effectively relieve the airway blockage that is causing snoring and interrupted sleep as well as recurrent tonsillitis. Tonsils do not usually grow back.

After surgery, complications may occur.

Only a few people—adults more than children—have bleeding complications after a tonsillectomy. Bleeding typically occurs within 24 hours of surgery or after about 7 days. People who have bleeding after a tonsillectomy should go to a hospital.

The airway may become blocked, most frequently in children who are under 2 years old and who had severe obstructive sleep apnea and in people who have morbid obesity or neurologic disorders or had significant obstructive sleep apnea before surgery. Complications are usually more common and serious among young children.

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