Written by:

Overview

What Is Acute Tonsillitis?

Acute tonsillitis is sudden inflammation and swelling of the tonsils, the small areas of tissue at the back of the throat. It is usually caused by a viral infection, although bacteria such as group A Streptococcus can also be responsible. Acute tonsillitis can affect children and adults and may cause a sore throat, fever, and pain when swallowing.

Symptoms

Symptoms of Acute Tonsillitis

  • Sore throat
  • Red or swollen tonsils (tonsillar inflammation)
  • White patches or pus on the tonsils (tonsillar exudate)
  • Painful swallowing (odynophagia)
  • Fever
  • Swollen neck glands (cervical lymph nodes)
  • Bad breath (halitosis)
  • Voice changes

How It Spreads

How Acute Tonsillitis Spreads

Tonsillitis itself is inflammation, but the viruses or bacteria causing it can spread through respiratory droplets, saliva, and close contact. Sharing utensils, cups, or drinks can also pass these germs between people. Whether tonsillitis is contagious depends on its cause, and contagiousness usually lasts while the underlying infection is active.

  • Wash your hands often with soap and water or use hand sanitizer.
  • Avoid sharing cups, drinks, food, or utensils with someone who is ill.
  • Cover coughs and sneezes with a tissue or your elbow.
  • Improve ventilation by opening windows or using suitable air filtration.
  • Stay home while feverish and follow a clinician’s advice about returning to school or work.

Risk Factors

Risk Factors for Acute Tonsillitis

  • School or daycare exposure
  • Close contact with an infected person
  • Frequent respiratory infections
  • Young age
  • Crowded living or classroom settings
  • A history of recurrent tonsillitis

Some risks can be reduced, such as sharing drinks, skipping handwashing, or spending close time with someone who is ill. Other factors, including age and a history of recurrent tonsillitis, cannot be changed. Reducing exposure may lower risk but cannot prevent every infection.

Complications

Complications of Acute Tonsillitis

  • Dehydration from painful swallowing or inability to drink
  • Peritonsillar abscess beside a tonsil
  • Airway obstruction from severe swelling
  • Spread of infection to nearby tissues or the bloodstream
  • Rare post-streptococcal complications affecting the kidneys, heart, or joints

Urgent complication signs

Get medical help promptly

Seek urgent medical assessment for worsening one-sided throat swelling, inability to swallow saliva, a muffled voice, difficulty opening the mouth, breathing difficulty, or signs of severe dehydration.

Diagnosis

How Acute Tonsillitis Is Diagnosed

A clinician will ask about the illness and examine the throat, including the appearance of the tonsils, fever, neck lymph nodes, cough, and possible exposure to an infection. They may also ask whether swallowing is possible and whether fluids can be kept down. This history and examination help guide decisions about testing and treatment.

  • A rapid strep test may be used when symptoms could be caused by group A Streptococcus.
  • A throat culture may be recommended when a rapid test is negative but strep infection remains a concern, especially in children.
  • Other testing may be considered when symptoms suggest mononucleosis or another condition.
  • Testing decisions vary by age, symptoms, examination findings, and local clinical guidance.

Because symptoms can overlap, the clinician may consider a viral infection, strep throat, mononucleosis, tonsil stones, or other causes of a sore throat. The appearance of the tonsils alone cannot reliably determine whether antibiotics are needed.

Treatment & Management

Acute Tonsillitis Treatment and Management

Supportive care at home

Most people can manage acute tonsillitis with plenty of fluids, rest, soothing warm or cool liquids, and lozenges when safe and age-appropriate. A clinician-approved pain or fever medicine may help relieve discomfort. Antibiotics do not treat viral tonsillitis and should be used only when prescribed for a bacterial cause; take the full prescribed course and do not use leftover medication.

When treatment needs to escalate

Prevention

Can Acute Tonsillitis Be Prevented?

  • Wash your hands frequently, especially after coughing, sneezing, or being around someone who is ill.
  • Avoid sharing food, drinks, cups, or utensils.
  • Clean frequently touched surfaces regularly.
  • Cover coughs and sneezes with a tissue or your elbow.
  • Improve indoor ventilation when people are together.
  • Avoid close contact with others while you are ill.

There is no routine screening test for acute tonsillitis. Prevention steps can lower the risk of spreading or catching the infections that cause it, but they cannot eliminate infections completely.

Outlook and Prognosis

Outlook for Acute Tonsillitis

Most uncomplicated cases of acute tonsillitis improve over several days to about a week, depending on the cause and treatment. Bacterial cases generally begin to improve after appropriate antibiotics, while viral cases improve as the immune system clears the infection. Rest, fluids, and symptom relief can support recovery.

Recurrent episodes, symptoms that do not improve as expected, or repeated missed school or work may prompt a discussion with an ear, nose, and throat specialist. Persistent symptoms can sometimes indicate another condition or a complication rather than typical tonsillitis.

When Should You See a Doctor

When Should You See a Doctor for Acute Tonsillitis?

  • Severe or worsening throat pain
  • Fever that is high, persistent, or returning
  • Symptoms lasting longer than expected
  • Recurrent episodes of tonsillitis
  • Suspected exposure to strep infection
  • Inability to maintain fluids
  • Tonsillitis symptoms in a young child

Seek urgent care

Know the emergency signs

Get urgent care for trouble breathing, inability to swallow saliva, drooling, rapidly worsening swelling, severe dehydration, confusion, or a muffled voice with one-sided throat swelling.