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Acute Pharyngitis and Tonsillitis

Acute Pharyngitis and Tonsillitis - What it is

Acute pharyngitis and tonsillitis occur when the pharynx and tonsils become infected with a virus or bacteria. They are common ailments that cause sore throat and the tonsils to become swollen and painful.

Acute Pharyngitis and Tonsillitis - Symptoms

Signs and symptoms of pharyngitis include:

  • Sore throat
  • Fever

If tonsillitis occurs, you will experience:

  • Severe sore throat
  • Painful and difficult swallowing
  • Referred pain to the ear
  • Fever and chills
  • Loss of voice (due to inflammation of voice box)
  • Headache
  • Tender and enlarged lymph glands in the neck
  • Red and swollen tonsils and white patches on the tonsils


Acute tonsillitis itself is usually not serious but can lead to complications if left untreated. Swollen tonsils can block the airway and cause airway obstruction leading to sleep apnoea.

The infection may spread to the surrounding tissue and neck and result in the collection of pus between the tonsil and tissues around it (peritonsillar infection and abscess). It can also spread to the neck causing pus collection in the neck (parapharyngeal abscess and retropharyngeal space abscess). You can present with difficulty swallowing, drooling, stiff neck or pain and difficulty breathing.

Acute Pharyngitis and Tonsillitis - How to prevent?

  • The viruses and bacteria that cause pharyngitis and tonsillitis are contagious. Personal hygiene is important to prevent infections and frequent hand washing is the best way. Wash your hands often, and encourage your children to do the same.
  • Other precautionary measures include not sharing drinking glasses or eating utensils, covering the mouth when sneezing or coughing and avoiding close contact with anyone who is sick.
  • Parents should keep their children at home if they are sick to prevent spreading the germs.

Acute Pharyngitis and Tonsillitis - Causes and Risk Factors

The pharynx and tonsils have lymphoid tissue (white blood cells) that form part of the defense mechanism against viruses and bacteria that enter the body through the nose or mouth.

Pharyngitis and tonsillitis are caused mainly by viruses. Less often, it may be the result of bacterial infection and antibiotic treatment will be required.

Most cases of sore throat are the result of acute pharyngitis. Tonsillitis occurs when the infection gets more serious, and the tonsils become painful and inflamed.

Tonsillitis caused by Viruses

The majority of tonsillitis are caused by viruses (like Adenovirus, Influenzae viruses, Parainfluenzae virus, Respiratory Syncytial Virus etc) that can affect the upper respiratory tract, including the virus that causes infectious mononucleosis (the Epstein- Barr virus). Tonsillitis can also be caused by bacterial infections (like Streptococcus species, Staphylococcus species).

Acute tonsillitis caused by the Epstein - Barr virus can cause infectious mononucleosis. It is also called ‘kissing disease’ because of its spread via saliva and it commonly affects adolescents and young adults. It is characterised by :

  • Sore throat
  • Fever
  • Enlarged cervical lymph nodes
  • Enlarged tonsils and fatigue
  • Other clinical manifestations are splenomegaly (enlarged spleen), hepatomegaly and hepatitis (enlarged liver and inflammation of the liver) and low platelet and white blood count.

Tonsilities caused by Bacteria

Acute tonsillitis due to a specific type of bacteria (Group A Streptococci) is called strept throat.

Symptoms caused by strep throat include :

  • A sudden onset of pain and pain on swallowing
  • Tender lymph glands in the neck
  • High spiking fever
  • A lack of upper respiratory tract symptoms (like running nose, nasal blockage).

As most cases of tonsillitis are caused by viruses, symptomatic treatment with painkillers, fever medications and hydration is enough. However, if the infection is caused by strep throat or another bacterial infection, treatment with antibiotics is needed.

School-going children are prone to viruses and bacteria that cause upper respiratory tract infection and tonsillitis. These tend to get passed on in childcare centres and schools where children are in close proximity.

causes of acute pharyngitis - SGH

Acute Pharyngitis and Tonsillitis - Diagnosis

The diagnosis of tonsillitis and its complications can be made by the history, physical examination and relevant radiological investigations. The doctor may order a full blood count or throat swab.

Acute Pharyngitis and Tonsillitis - Treatments

Acute tonsillitis caused by a virus is usually self-limiting and symptomatic treatment is sufficient. However, if the tonsillitis is caused by a bacterial infection, antibiotics may be prescribed that needs to be completed. Stopping the antibiotics prematurely may lead to the bacteria developing a resistance to it.


Most cases of tonsillitis are caused by viral infection and antibiotics is not necessary. It is usually self-limiting and symptomatic treatment to relieve pain and inflammation is all that is required. It takes about a week for full recovery. Drinking lots of water to prevent dehydration is usually advised.

  • Drink warm, soothing liquids - such as soup, broth and tea.
  • Gargle with warm salt water.
  • Take paracetamol or ibuprofen to help reduce fever and decrease pain.

Children should not be prescribed aspirin because of the risk of Reye’s syndrome - a potentially life-threatening illness causing encephalopathy (brain damage) and fatty liver. Persons diagnosed with infectious mononucleosis should not exert themselves or engage in strenuous activity for a month for fear of splenic rupture.


Surgical removal of the tonsils (tonsillectomy) for tonsillitis may be recommended when a patient has:

  • Seven or more serious throat infections in one year
  • Five or more serious throat infections every year over a two year period
  • Three or more serious throat infections every year over a threeyear period
  • Chronic tonsillitis

Tonsillectomy may also be recommended to treat an abscess that does not improve with antibiotic treatment, or if breathing is blocked by swollen tonsils.

A complete recovery may take up to 2 weeks.

Acute Pharyngitis and Tonsillitis - Preparing for surgery

Acute Pharyngitis and Tonsillitis - Post-surgery care

Acute Pharyngitis and Tonsillitis - Other Information

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth