Tonsillitis and Peritonsillar Abscess — Definitions, Comparisons and Exam Traps

Tonsillitis is inflammation of the palatine tonsils, usually caused by infection. Patients may have sore throat, fever, painful swallowing and erythematous or exudative tonsils. Most episodes are viral, while group A Streptococcus is the important bacterial cause to recognise. The presence of exudate alone does not prove a streptococcal infection.

The opening assessment must establish whether the presentation is an uncomplicated sore throat or a potentially dangerous deep infection. Difficulty managing secretions, respiratory distress, marked unilateral swelling, trismus or a muffled voice should redirect attention toward airway safety and complications. The priority can change before the cause of the tonsillitis is fully established.

Exam questions commonly compare uncomplicated tonsillitis with quinsy, or peritonsillar abscess. Tonsillitis primarily affects the tonsillar tissue; quinsy is a collection in the peritonsillar space. The distinction matters because an abscess may need procedural drainage as well as antimicrobial treatment. Increasing unilateral symptoms are more informative than the word “pus” alone.

The palatine tonsil lies between the palatoglossal arch anteriorly and palatopharyngeal arch posteriorly. The palatoglossus and palatopharyngeus muscles form the respective pillars. The superior constrictor lies lateral to the tonsil, separated by the capsule and peritonsillar plane that are important during surgical dissection.

The peritonsillar space lies between the fibrous tonsillar capsule and the surrounding pharyngeal musculature. An abscess developing here can bulge the soft palate and move the affected tonsil medially. Inflammation adjacent to the pterygoid region explains the characteristic restriction of mouth opening. This relationship is more useful than treating trismus as a nonspecific sore-throat symptom.

The palatine tonsils are part of Waldeyer lymphoid ring, together with the pharyngeal, tubal and lingual tonsils. The adenoids are the pharyngeal tonsil in the nasopharynx. Do not place them in the tonsillar fossa, and do not confuse removal of the palatine tonsils with an isolated adenoid procedure.

Cough, coryza and conjunctivitis favour a viral upper respiratory process. Fever, tonsillar exudate, tender anterior cervical nodes and absence of cough raise the probability of streptococcal infection. These findings form the basis of Centor assessment, but they estimate probability rather than identify the organism with certainty.

When group A streptococcal infection is suspected, rapid antigen testing or a throat culture can guide treatment according to the clinical setting and applicable guidance. A negative or positive test must be considered alongside the history and examination. Clinical scores are tools for rational testing and prescribing, not instructions to give antibiotics for every inflamed tonsil.

Epstein–Barr virus can produce marked exudative tonsillitis with systemic features. Generalised or posterior cervical lymphadenopathy and prolonged fatigue should prompt consideration of mononucleosis. Aminopenicillin exposure in that setting can be associated with a rash. The diagnostic trap is equating white tonsillar exudate with a need for amoxicillin without considering the broader syndrome.

Treatment of uncomplicated viral tonsillitis is supportive: adequate fluids, appropriate analgesia and advice on worsening symptoms. Reduced intake can cause dehydration, especially when swallowing is painful. Assessment should therefore include the ability to drink and manage saliva rather than relying only on the appearance of the tonsils.

When treatment for group A Streptococcus is indicated, penicillin or amoxicillin is commonly used, with alternatives selected for allergy and local guidance. The objective includes reducing complications and transmission, not simply removing exudate. This revision page avoids a universal dose because age, formulation, allergy history and treatment pathway affect prescribing.

Bacterial tonsillitis can be followed by local suppurative complications such as quinsy and by immune-mediated complications including acute rheumatic fever and poststreptococcal glomerulonephritis. These are different mechanisms: the abscess is local pus formation, whereas the latter conditions reflect a host response after infection. Their management cannot be inferred from the appearance of the original throat alone.

Quinsy typically presents with severe unilateral throat pain, painful swallowing, fever, ipsilateral referred ear pain, trismus and a muffled hot-potato voice. Examination may show unilateral peritonsillar or soft-palate swelling, medial displacement of the affected tonsil and deviation of the uvular base away from the affected side. The uvular finding is supportive but not present in every patient.

The abscess commonly involves the superior tonsillar region and is usually polymicrobial, with aerobic and anaerobic organisms. Group A streptococci, streptococcal anginosus-group organisms and oral anaerobes are important considerations. Do not reduce treatment planning to the same narrow assumptions used for uncomplicated streptococcal tonsillitis.

Imaging is useful when examination is limited, the diagnosis is uncertain or extension into another deep neck space is suspected. Ultrasound can identify a collection and guide drainage; contrast-enhanced CT can define a deep infection and complications. A classic examination may support the diagnosis, but severe trismus or an atypical course lowers confidence in an examination-only approach.

1. Assess airway patency and signs of respiratory compromise before detailed testing.
2. Arrange ENT or emergency assessment, provide analgesia and correct dehydration.
3. Begin appropriate antibiotics covering the expected streptococci and oral anaerobes; choose the route according to severity and ability to swallow.
4. Assess the collection for needle aspiration or incision and drainage by an appropriately trained clinician.
5. Consider tonsillectomy in selected circumstances, including recurrence, obstructive disease or a collection difficult to access.
6. Reassess oral intake, symptom improvement and evidence of persistent or extending infection.

A formed abscess often needs drainage, but the decision is individualised; selected uncomplicated cases may receive medical management with close follow-up. Avoid the absolute statement that every suspected peritonsillar infection must undergo an identical procedure. Peritonsillar cellulitis, a small collection and a large complicated abscess are different clinical situations.

Drainage takes place near major vessels, including the internal carotid artery, and airway access can be difficult. The examination principle is prompt specialist assessment and safe drainage planning rather than a needle-depth formula. Corticosteroids may be used as an adjunct for pain and swelling in selected patients; they do not replace antibiotics, drainage assessment or airway stabilisation.

For children with recurrent throat infection, a commonly used documented threshold is at least seven episodes in the preceding year, at least five episodes per year for two years, or at least three episodes per year for three years. These are alternatives, not a requirement to satisfy every time pattern. They support consideration of surgery rather than an automatic operation.

Each qualifying episode should be documented as sore throat with a supporting feature such as fever above 38.3°C, cervical adenopathy, tonsillar exudate or a positive group A streptococcal test. A vague history of “many sore throats” is weaker than documented tonsillitis with relevant findings. Below the threshold, watchful waiting is generally recommended unless modifying factors favour surgery.

Relevant modifying factors include multiple antibiotic allergies or intolerance, PFAPA and recurrent peritonsillar abscess. Sleep-disordered breathing or obstructive sleep apnoea related to adenotonsillar hypertrophy is a separate indication pathway. Suspicious asymmetry or possible malignancy also requires evaluation. Do not apply a recurrent-infection count as the sole criterion for every reason to remove a tonsil.

Haemorrhage is the complication that must not be missed. Primary bleeding occurs during the operation; reactionary bleeding occurs within the first 24 hours; secondary bleeding usually appears at 5–10 days, often with infection. These terms classify timing. Any postoperative throat bleeding needs urgent assessment regardless of its label or an initially small amount.

Pain can reduce oral intake and cause dehydration. Nausea and vomiting can compound the problem. Airway or respiratory compromise is another important early complication, particularly in patients with relevant obstructive disease. Postoperative care therefore assesses hydration, analgesia, bleeding and breathing together.

The glossopharyngeal nerve lies deep to the lateral tonsillar region and can be affected during tonsillectomy. This relation helps explain referred otalgia and possible taste disturbance. The tonsil is supplied by branches of the external carotid system, including facial, lingual, ascending pharyngeal and maxillary contributions. These relations explain why the dissection plane and haemostasis matter.

A peritonsillar infection can extend to parapharyngeal or other deep neck spaces and may threaten the airway. Aspiration of material from a ruptured abscess is another complication. Severe or progressive symptoms, neck swelling, systemic illness or a poor response to treatment justify reassessment for extension rather than repeated treatment of a presumed uncomplicated sore throat.

Lemierre syndrome involves septic thrombophlebitis of the internal jugular vein with possible septic emboli. It is a serious complication associated with oropharyngeal infection and anaerobic organisms, especially Fusobacterium. Recognise the vascular complication separately from the local abscess: persistent systemic illness or a deep-neck pattern can signal a different level of disease.

Retropharyngeal abscess, parapharyngeal abscess and epiglottitis also enter the differential of severe sore throat or airway symptoms. The decisive first step is airway assessment, not forcing every presentation into the quinsy label. For revision, link the location of infection to examination clues and then connect those clues with the appropriate urgency and investigation.