Acute pharyngitis

Last updated: November 2020

Acute inflammation of the tonsils and pharynx. The majority of cases are of viral origin and do not require antibiotic treatment. Group A streptococcus (GAS) is the main bacterial cause, and mainly affects children aged 3 to 14 years.

Acute rheumatic fever (ARF), a serious late complication of GAS pharyngitis, can be prevented with antibiotic treatment.

One of the main objectives of assessing acute pharyngitis is to identify patients requiring antibiotic treatment.

Clinical features

• Features common to all types of pharyngitis: throat pain, dysphagia (difficulty swallowing), inflammation of the tonsils and pharynx, tender anterior cervical lymph nodes, with or without fever.

• Specific features, depending on the cause:

Common forms:

• Erythematous (red throat) or exudative (red throat and whitish exudate) pharyngitis: this appearance is common to both viral and GAS pharyngitis. Centor criteria help assessment and decrease the empirical use of antibiotics in settings where rapid testing for GAS is not available. A Centor score of less than 2 rules out GAS infection [1] Citation 1. Fine AM, Nizet V, Mandl KD. Large-scale validation of the Centor and McIsaac scores to predict group A streptococcal pharyngitis. Arch Intern Med. 2012;172(11):847-852.
  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3627733/ [Accessed 20 October 2020] [2] Citation 2. National Institute for Health and Care Excellence. Sore throat (acute): antimicrobial prescribing. 2018.
  http://www.nice.org.uk/ng84 [Accessed 20 October 2020] . Nevertheless, in patients with risk factors (immunosuppression, personal or family history of ARF) for poststreptococcal complications, or for local or general complications, do not use Centor score and prescribe empirical antibiotic treatment.

Centor criteria

In patients over 14 years, the probability of GAS pharyngitis is low. Infectious mononucleosis (IM) due to the Epstein-Barr virus should be suspected in adolescents and young adults with extreme fatigue, generalized adenopathy and often splenomegaly.
Erythematous or exudative pharyngitis may also be associated with gonococcal or primary HIV infection. In these cases, the diagnosis is mainly prompted by the patient's history.

• Pseudomembranous pharyngitis (red tonsils/pharynx covered with an adherent greyish white false membrane): see Diphtheria, Chapter 2.
• Vesicular pharyngitis (clusters of tiny blisters or ulcers on the tonsils): always viral (coxsackie virus or primary herpetic infection).
• Ulcero-necrotic pharyngitis: hard and painless syphilitic chancre of the tonsil; tonsillar ulcer soft on palpation in a patient with poor oral hygiene and malodorous breath (Vincent tonsillitis).

Other forms of pharyngitis:

• Spots on oral mucosa (Koplik’s spots) accompanied by conjunctivitis and skin rash (see Measles, Chapter 8).
• “Strawberry” (red and bumpy) tongue accompanied by a skin rash: scarlet fever caused by GAS.

• Local complications:

Peritonsillar, retropharyngeal or lateral pharyngeal abscess: fever, intense pain, dysphagia, hoarse voice, trismus (limitation of mouth opening), unilateral deviation of the uvula.

• General complications:
  • Complications due to the toxin: diphtheria (see Diphtheria, Chapter 2).
  • Poststreptococcal complications: ARF, acute glomerulonephritis.
  • Signs of serious illness in children: severe dehydration, severe difficulty swallowing, upper airway compromise, deterioration of general condition.

• Differential diagnosis: epiglottitis (see Epiglottitis, Chapter 2).

Treatment

• Symptomatic treatment (fever and pain): paracetamol or ibuprofen PO (Fever, Chapter 1).

• Centor score ≤ 1: viral pharyngitis, which typically resolves within a few days (or weeks, for IM): no antibiotic treatment.

• Centor score ≥ 2 or scarlet fever: antibiotic treatment for GAS infections [3] Citation 3. Group A Streptococcal Disease, Centers for Disease Control and Prevention. Atlanta (GA): CDC; 2020. 
  https://www.cdc.gov/groupastrep/diseases-hcp/strep-throat.html [Accessed 20 October 2020] :
  • If single-use injection equipment is available, benzathine benzylpenicillin is the drug of choice as streptococcus A resistance to penicillin remains rare; it is the only antibiotic proven effective in reducing the incidence of rheumatic fever; and the treatment is administered as a single dose.
    benzathine benzylpenicillin IM
    Children under 30 kg (or under 10 years): 600 000 IU single dose
    Children 30 kg and over (or 10 years and over) and adults: 1.2 MIU single dose
  • Penicillin V is the oral reference treatment, but poor adherence is predictable due to the length of treatment.
    phenoxymethylpenicillin (penicillin V) PO for 10 days
    Children 1 to < 6 years: 250 mg 2 times daily
    Children 6 to < 12 years: 500 mg 2 times daily
    Children 12 years and over and adults: 1 g 2 times daily
    Children under 1 year: 125 mg 2 times daily
  • Amoxicillin is an alternative and the treatment has the advantage of being relatively short. However, it can cause adverse skin reactions in patients with undiagnosed IM and thus should be avoided when IM has not been excluded
    amoxicillin PO for 6 days
    Children: 25 mg/kg 2 times daily
    Adults: 1 g 2 times daily
  • Macrolides should be reserved for penicillin allergic patients as resistance to macrolides is frequent and their efficacy in the prevention of rheumatic fever has not been studied. 
    azithromycin PO for 3 days
    Children: 20 mg/kg once daily (max. 500 mg daily)
    Adults: 500 mg once daily

• Gonococcal or syphilitic pharyngitis: as for genital gonorrhoea (Chapter 9) and syphilis (Chapter 9).

• Diphtherial pharyngitis: see Diphtheria (Chapter 2).

• Vincent tonsillitis: metronidazole or amoxicillin.

• Peritonsillar retropharyngeal or lateral pharyngeal abscess: refer for surgical drainage.

• If signs of serious illness or epiglottitis are present in children: hospitalise.