Peritonsillar abscess
Other names	Quinsy, quinsey
Right sided peritonsillar abscess
Specialty	Otorhinolaryngology
Symptoms	Fever, throat pain, trouble opening the mouth, change to the voice[1]
Complications	Blockage of the airway, aspiration pneumonitis[1]
Causes	Multiple types of bacteria[1]
Risk factors	Streptococcal pharyngitis[1]
Diagnostic method	Based on the symptoms[1]
Differential diagnosis	Retropharyngeal abscess, infectious mononucleosis, epiglottitis, cancer[1]
Treatment	Remove pus, antibiotics, fluids, pain medication, steroids[1]
Frequency	~3 per 10,000 per year (USA)[1]

Peritonsillar abscess (PTA), also known as quinsy, is an accumulation of pus due to an infection behind the tonsil.^[2] Symptoms include fever, throat pain, trouble opening the mouth, and a change to the voice.^[1] Pain is usually worse on one side.^[1] Complications may include blockage of the airway or aspiration pneumonitis.^[1]

PTA is typically due to infection by a number of types of bacteria.^[1] Often it follows streptococcal pharyngitis.^[1] They do not typically occur in those who have had a tonsillectomy.^[1] Diagnosis is usually based on the symptoms.^[1] Medical imaging may be done to rule out complications.^[1]

Treatment is by removing the pus, antibiotics, sufficient fluids, and pain medication.^[1] Steroids may also be useful.^[1] Admission to hospital is generally not needed.^[1] In the United States about 3 per 10,000 people per year are affected.^[1] Young adults are most commonly affected.^[1]

Physical signs of a peritonsillar abscess include redness and swelling in the tonsillar area of the affected side and swelling of the jugulodigastric lymph nodes. The uvula may be displaced towards the unaffected side.^[3]

Unlike tonsillitis, which is more common in children, PTA has a more even age spread, from children to adults. Symptoms start appearing two to eight days before the formation of an abscess. A progressively severe sore throat on one side and pain during swallowing (odynophagia) usually are the earliest symptoms. As the abscess develops, persistent pain in the peritonsillar area, fever, a general sense of feeling unwell, headache, and a distortion of vowels informally known as "hot potato voice" may appear. Neck pain associated with tender, swollen lymph nodes, referred ear pain and foul breath are also common. While these signs may be present in tonsillitis itself, a PTA should be specifically considered if there is limited ability to open the mouth (trismus).^[3]

While most people recover uneventfully, there is a wide range of possible complications.^[4] These may include:^[1]

• Retropharyngeal abscess
• Extension of abscess in other deep neck spaces leading to airway compromise (see Ludwig's angina)
• Airway obstruction
• Aspiration pneumonitis
• Lung abscess (following rupture)
• Sepsis
• Life-threatening hemorrhage (following erosion or septic necrosis into the carotid sheath of the neck)
• Glomerulonephritis and rheumatic fever (chronic complications of strep throat)

Difficulty swallowing can lead to decreased oral intake and dehydration.

PTA usually arises as a complication of an untreated or partially treated episode of acute tonsillitis. The infection, in these cases, spreads to the peritonsillar area (peritonsillitis). This region comprises loose connective tissue and is hence susceptible to formation of an abscess. PTA can also occur de novo. Both aerobic and anaerobic bacteria can be causative. Commonly involved aerobic pathogens include Streptococcus, Staphylococcus and Haemophilus. The most common anaerobic species include Fusobacterium necrophorum, Peptostreptococcus, Prevotella species, and Bacteroides.^{[5][6][7][8][9][10]}

Diagnosis is usually based on the symptoms.^[1] Medical imaging may be done to rule out complications.^[1] Medical imaging may include CT scan, MRI, or ultrasound is also useful in diagnosis.^[1]

Medical treatment with antibiotics, volume repletion with fluids, and pain medication is usually adequate, although in cases where airway obstruction or systemic sepsis occurs, surgical drainage may be necessary.^[1][11] Corticosteroids may also be useful.^[1] Admission to hospital is generally not needed.^[1]

The infection is frequently penicillin resistant.^[1] There are a number of antibiotics options including amoxicillin/clavulanate, ampicillin/sulbactam, clindamycin, or metronidazole in combination with benzylpenicillin (penicillin G) or penicillin V.^[1][12] Piperacillin/tazobactam may also be used.^[1]

The pus can be removed by a number of methods including needle aspiration, incision and drainage, and tonsillectomy.^[1] Incision and drainage may be associated with a lower chance of recurrence than needle aspiration but the evidence is very uncertain. Needle aspiration may be less painful but again the evidence is very uncertain.^[13]

Treatment can also be given while a patient is under anesthesia, but this is usually reserved for children or anxious patients. Tonsillectomy can be indicated if a patient has recurring peritonsillar abscesses or a history of tonsillitis. For patients with their first peritonsillar abscess most ENT-surgeons prefer to "wait and observe" before recommending tonsillectomy.^[14]

It is a commonly encountered otorhinolaryngological (ENT) emergency.^[14]

The number of new cases per year of peritonsillar abscess in the United States has been estimated approximately at 30 cases per 100,000 people.^[15] In a study in Northern Ireland, the number of new cases was 10 cases per 100,000 people per year.^[16] In Denmark, the number of new cases is higher and reaches 41 cases per 100,000 people per year.^[17] Younger children who develop a peritonsillar abscess are often immunocompromised and in them, the infection can cause airway obstruction.^[18]

The condition is often referred to as "quincy", "quinsy",^[19] or "quinsey", anglicised versions of the French word esquinancie which was originally rendered as squinsey and subsequently quinsy.^[20]

• Sultan Tekish of Kwarezm^[21]
• Osceola^[22]
• Michel de Montaigne^[23]
• Pope Adrian IV
• Dan Minogue, the captain/coach of Australian Rules football team Richmond was rumoured to be dead a week before the 1920 VFL Grand Final, but in fact, was in his hometown of Bendigo recovering from quinsy.
• George Washington was believed to have died of complications arising from quinsy, but is now thought to have died from epiglottitis.^[24]
• James Gregory of the band The Ordinary Boys almost died from quinsy because it was left untreated for so long before emergency treatment was started.^[25]
• Eiichiro Oda, author of the best-selling One Piece manga, was hospitalized due to complications.^[26]
• Ian Maclaren died of complications from quinsy while on a lecture tour of the United States.^[27]

The ancient Roman goddess Angerona was claimed to cure quinsy (Latin angina) in humans and sheep.^[28][29]