Introduction 

Peritonsillar abscess is one of the most common deep neck infections.¹ The condition typically presents with a sore throat, difficulty swallowing and a muffled/ ‘hot potato’ voice. It can be treated in several ways. 

Key points of how to deal with peritonsillar abscess:¹

• Seek medical treatment: Healthcare professionals can give a diagnosis and recommend the best thing to do
• Treatment options: Usually abscess’ are drained to alleviate symptoms. The two procedures used are incision and drainage and needle aspiration
• Antibiotics: It is common with a peritonsillar abscess to be given antibiotics and it is vital that they are taken for the recommended time
• Pain management: Pain relief can be used to help alleviate the symptoms

This article covers the key features of peritonsillar abscesses including symptoms, diagnosis, complications, preventative measures and treatment.

Peritonsillar abscess, also known as ‘quinsy’, is one of the most common deep neck infections. The condition is characterised as collections of pus in the peritonsillar space – the area between the superior constrictor muscle and the tonsillar capsule.¹ Peritonsillar abscess tends to occur following an episode of acute tonsilitis. It is quite rare to develop a peritonsillar abscess without having a history of symptoms relating to acute tonsilitis. According to the National Institute of Health (NIH), the most common group to be affected by a peritonsillar abscess is the adolescent population, though it can affect anyone.²

Anatomy of the tonsils 

The tonsils help to play a role in the body’s immune system as they can stop germs entering the body via the nose or the mouth.³ The tonsils are bundles of lymphatic tissue located in the pharynx. There are four different kinds of tonsils that form Waldeyers ring.⁴  These are the pharyngeal tonsils, tubal tonsils, palatine tonsils and lingual tonsils. The tonsils contain T cells, B cells and macrophages, which are components of the immune system that help to fight off infection.⁴ The two palatine tonsils are found on the right and left of the back of the throat and can be seen when you open your mouth. The lingual tonsils are at the far back of the base of the tongue.³

Causes of peritonsillar abscess 

The pathophysiology (abnormal physiological process resulting in disease) of peritonsillar abscess is not fully understood. A current theory suggests that an infection may develop elsewhere and spread to the tonsil capsule, leading to peri-tonsillitis, which then can result in abscess formation.²

There are many reasons as to why peritonsillar abscesses occur. The main reason is following an episode of acute tonsilitis.² However, infectious mononucleosis, also known as glandular fever, can also lead to abscess formation. Other less common things that might contribute to peritonsillar abscess formation might be smoking and chronic periodontal disease.² The three most common bacteria known to cause peritonsillar abscesses include staphylococcal, pneumococcal and haemophilic organisms, though other bacteria may also be implicated. ⁸

Peritonsillar abscesses may not originate in the tonsils. It is thought that Weber’s glands contribute to the formation of peritonsillar abscesses. Weber’s glands are minor mucous salivary glands that are superior to (above) the tonsils in the soft palate and connect by a duct to the tonsil surface.⁵  The purpose of Weber’s glands is to clear debris and help with the digestion of food particles. If Weber’s glands become inflamed, local cellulitis (infection) may develop.  If the infection worsens, the duct to the surface of the tonsils becomes trapped due to the surrounding inflammation. This can then result in necrosis of the tissue and pus formation.⁵

Signs and symptoms 

 Symptoms of peritonsillar abscess include:

• Fever
• Foul-smelling breath
• Sore throat (typically worse on the affected side)
• Dysphagia (difficulty swallowing)
• Headache 
• Malaise

Physical signs may include trismus, where the individual struggles to open their mouth. This is due to inflammation and spasms of the masticator muscles. Other physical examination results include drooling, muffled ‘hot potato’ voice and a unilateral (one-sided) tonsillar bulge. The drooling occurs because of dysphagia (difficulty swallowing) and odynophagia (pain when swallowing), which leads to pooling of saliva.  There may also be swollen lymph nodes in the neck, resulting in a unilateral tonsillar bulge. Typically,  inspecting the mouth will reveal swelling and redness of the anterior tonsillar and soft palate. The tonsil will be displaced away from the uvula.⁵

Diagnosis 

Diagnosis of a peritonsillar abscess is typically made through taking-thorough history. The health professional might ask about the symptoms you may have experienced and then complete a physical examination. According to NICE guidelines, the FEVERPain criteria⁷ is used to assess the likelihood of a streptococcal infection and whether or not there is a need for antibiotic treatment. There is one point for each present feature, with a maximum score of 5. The criteria include: 

• Fever during the last 24 hours
• Purulence (pus formation)
• Attend rapidly (within 3 days after onset of symptoms)
• Severely inflamed tonsils
• No cough 

It is important to note that some of the symptoms experienced in peritonsillar abscess might also be seen in peritonsillar cellulitis, infectious mononucleosis/glandular fever, epiglottitis and tonsilitis. Imaging isn’t something that is routinely done to form a diagnosis, but in some cases CT or ultrasound can be useful.⁸ The gold standard for peritonsillar abscess is needle aspiration, where pus is collected. Once aspiration is performed the fluid can be sent for culture sensitivity to find out which organism is the root cause, and to guide treatment.⁶

Treatment options 

 Most patients will typically present to the GP or the emergency department.²  People with peritonsillar abscesses who come into the hospital are typically given intravenous (through a vein) fluids. Due to trismus and not being able to drink or eat, dehydration can occur. Antibiotics are then given intravenously until they improve and can switch to oral antibiotics. It is quite common to have a course of antibiotics for 14 days. Examples of antibiotics used include amoxicillin and clindamycin. For pain and fever relief, analgesia and antipyretics can be given. Treatment can vary from person to person. Some people might be treated with antibiotics and steroids alone, whereas others might need aspiration or incision and drainage.⁹  Aspiration local incision and drainage tend to occur with local analgesia administered to the site. There is currently limited data to suggest whether incision and drainage or needle aspiration is better. A needle aspiration occurs by numbing the area using a spray and then using a needle that has a syringe attached to withdraw the pus from the area. Needle aspirations tend to be used for smaller abscesses. This tends to be less of an invasive procedure compared to incision and drainage. Incision and drainage tend to be better suited for individuals with larger abscesses. Incision and drainage involve making a small cut in the affected region and using suction to remove the pus.⁹

Complications 

A number of complications can occur as a result of a peritonsillar abscess. These include: 

airway obstruction, aspiration pneumonitis and lung abscess secondary to the rupturing of the peritonsillar abscess. Death can occur due to an erosion causing a haemorrhage (bleed)  into the carotid sheath (part of the neck containing vital nerves and blood vessels). Infection may spread into the tissues of the deep neck. If infection occurs from group A streptococcus bacteria, this could progress to glomerulonephritis or rheumatic fever. It is also possible that another episode of peritonsillar abscess can occur.⁵

Recovery and aftercare

Most patients tend to recover within 4-7 days of the onset of illness. Once patients are discharged from hospital, usually after 24 to 48 hours, a soft diet, hydrating well, and taking anti-inflammatory medications such as ibuprofen can help.⁹ If symptoms persist, it is important to inform a healthcare professional. It is important that the antibiotic course is completed to ensure that the infection is eliminated completely and there is a much lower risk of it recurring. Not completing the antibiotic course can make the infection harder to treat in the future.⁵ It is vital to seek treatment if any of the following symptoms occur:⁹

• Fever
• Neck stiffness
• Bleeding
• Neck mass that is enlarging
• Neck or throat pain that is worsening 
• Worsening trismus 

Prevention strategies

To prevent peritonsillar abscesses from occurring it is important to seek medical treatment urgently, practice good oral hygiene and not smoke. It is also important to ensure that there is appropriate management and treatment of other conditions like tonsilitis so that it does not progress to peritonsillar abscess formation.⁹

Summary

In summary, a peritonsillar abscess can present with many symptoms and it tends to present after an episode of acute tonsilitis. The main symptoms experienced are fever, sore throat, drooling and inability to open the jaw. It is often diagnosed by a healthcare professional and treatment may include antibiotics, pain relief and/or incision and drainage or aspiration depending on the course of treatment taken. Complications of a peritonsillar abscess can occur, such as airway obstruction and aspiration pneumonitis. Most patients recover within 4-7 days with appropriate treatment. It is important that medical treatment is sought early to reduce the risk of complications.