Each month, Clinical Advisor makes one new clinical feature available ahead of print. Don’t forget to take the poll. The results will be published in the next month’s issue.

A peritonsillar abscess (PTA) is a purulent infection with abscess formation between the palatine tonsil and its capsule.1 These growths are often a complication of recent or current tonsillitis.

Approximately 30% of all PTAs occur in persons aged 20 to 40 years,2 occurring most often from April to May and again from November to December, which coincides with the highest incidence of streptococcal pharyngitis and exudative tonsillitis.1 Although seldom affected (unless they are immunocompromised), the infection can cause significant airway obstruction in young children. PTAs affect males and females equally.

Continue Reading

Evidence shows that chronic tonsillitis or multiple trials of oral antibiotics for acute tonsillitis may predispose an individual to the development of a PTA.3

Group A hemolytic Streptococcus is the most common cause of PTA; other possible causes are Staphylococcus aureus; Haemophilus influenza; and various anaerobes, including Peptostreptococcus and Fusobacterium. Polymicrobial infections are also common (Table 1).1,3,4

Abscess formation begins two to eight days after the onset of symptoms.4 Infection spreads from the tonsil— usually unilateral — into surrounding soft tissue, resulting in a collection of pus.

Which of the following should not be considered in PTA’s differential diagnosis?

Table 1. Organisms commonly associatedwith peritonsillar abscess

Aerobic bacteria Anaerobic bacteria
Group A Streptococcus Fusobacterium
Staphylococcus aureus Peptostreptococcus
Haemophilus influenzae Pigmented Prevotella
Streptococcus pyogenes Bacteroides

  1. Brook I. J Oral Maxillofac Surg. 2004;62:1545-1550.
  2. Kieff DA et al. Otolaryngol Head Neck Surg. 1999;120:57-61.

Additional evaluation of surrounding deep neck spaces is important because the abscess in the peritonsillar space may continue to spread and involve the parapharyngeal and retropharyngeal spaces. 

To prevent complications and further propagation of the infectious process, providers must be aware of the typical clinical presentation and diagnostic strategies to quickly assess and appropriately treat patients with PTA.2

Although unlikely with isolated PTA, significant edematous peritonsillar tissues may obstruct the airway, which is a life-threatening medical emergency. Sore throat associated with stridor and increased respiratory effort can signal imminent respiratory distress and requires immediate evaluation and management in a hospital emergency department.4

Making the diagnosis

PTAs may present with a variety of symptoms, but the onset is usually marked by a sore throat. Symptoms typically develop three to five days before a patient seeks medical evaluation, and time from onset of symptoms to abscess formation is approximately two to eight days.

Patients with a PTA appear ill and may be afebrile at first, but as the abscess progresses, a fever may develop. Presenting symptoms associated with a developing PTA may include severe sore throat, fever as high as 103°F (39°C), headache, malaise, odynophagia or drooling, neck pain, dysphagia and otalgia. More severe symptoms may indicate illness other than simple viral or streptococcal pharyngitis and require immediate medical care (Table 2).5

Table 2. Red flags in a patient with sore throat

Persistence of symptoms longer than one week without improvement
Respiratory difficulty, particularly stridor
Difficulty swallowing
A palpable mass
Blood, even a small amount, in the pharynx or ear
Source: Andreoli TE et al. Cecil Essentials of Medicine. 8th edition. Philadelphia, Pa.: Saunders-Elsevier; 2010:949.

A PTA is usually diagnosed based on patient history and a physical examination (Table 3).6 Physical exam findings indicative of a diagnosis of PTA include trismus (inability to open the mouth because of muscle spasms), inferior and medial displacement of the tonsil, displaced soft palate/uvula, change in voice (i.e., “hot potato” voice), rancid breath, tonsillar erythema, exudate on the tonsil, cervical lymphadenitis in the anterior chain and asymmetric tonsillar hypertrophy.

Table 3. Clinical differentiation of common conditions arising as sore throat

Feature Viral pharyngitis Bacterial tonsillitis Peritonsillar abscess Epiglottitis
Tonsillar enlargement Usual Rare None None
Tonsillar exudates Occasional (mononucleosis) Usual Often None
Tonsillar asymmetry None None Usual None
Trismus None None Usual None
Cervical adenopathy Occasional Usual (tender) Usual (tender) None
Tender larynx Rare None None Usual
Source: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa.: Elsevier; 2008:2889.