The most common infectious causes are viral or group A haemolytic streptococcus (GABHS). Group A Streptococcal infection is more likely in the winter/spring, and in children aged 5 – 15.

Group A haemolytic streptococcus (streptococcus pyogenes) is the infective agent responsible for the most serious complications of tonsillopharyngitis. For example: –

• Suppurative complications: – otitis media, sinusitis and peritonsillar abscess (quinsy)
• Non-suppurative complications: – rheumatic fever and post-streptococcal glomerulonephritis.

Clinical features: –

• Acute sore throat with other associated symptoms such as fever, headache & vomiting.
• Abdominal symptoms such as pain and vomiting are common in children
• Lymphadenopathy in the neck is common in both viral and GABHS infection but the presence of conjunctivitis is more specifically associated with adenoviral infection.
• Specific findings that can help in the DD: –

Finding	Diagnosis
Tonsillo-pharyngeal or palatal petechiae	GABHS infection or infectious mononucleosis
Unilateral peritonsillar swelling	Peritonsillar abscess
Grey pseudo-membrane on the pharynx	Diphtheria
Strawberry tongue	Scarlet fever or Kawasaki’s disease
Posterior pharyngeal swelling or oedema	Retropharyngeal abscess

There are a number of red flag symptoms and signs that should prompt the clinician to consider a more serious cause for a sore throat, including:

• Significant systemic upset
• Severe pain
• Stridor
• Severe neck stiffness
• Inability to swallow / drooling of saliva
• Patient holding a tripod position

Patients with impending airway obstruction may present with a sore throat. A patient with stridor, inability to swallow or adopting a tripod position must be managed carefully and with senior anaesthetic and otolaryngology support.

Diagnosis: –

1. Rapid streptococcal antigen testing (Although included in NICE guidance, not all UK EDs have access to rapid streptococcal antigen testing.)
2. A rising antistreptolysin O titre (ASOT) provides the gold standard criteria for immunologically significant GABHS infection. However, it is impractical and unnecessary in the vast majority of cases.
3. Heterophile antibody tests for infectious mononucleosis e.g., Monospot and Paul Bunnell
4. Covid-19 swab – It is recognised that sore throat can be a symptom of Covid-19. By itself it is not necessitate a PCR test, however clinicians should consider if there are other symptoms such as fever, new continuous cough or loss/change to sense or taste or smell
5. Deranged liver function tests are present in 90% of patients with Infectious Mononucleosis

Management: –

If the person: is systemically very unwell, or has symptoms and signs of a more serious illness or condition, or has high risk of complications — Offer an immediate antibiotic. Examples: –

• Marked systemic upset
• An increased risk of complications;
  • Immunosuppressed patients e.g., diabetics or taking disease modifying anti-rheumatic drugs
  • History of valvular heart disease
  • History of rheumatic fever
• An outbreak of GABHS infection within an institution (e.g., barracks / boarding school)
• A history of repeated episodes of proven GABHS infection

To differentiate between viral causes, and the potentially more serious GABHS infection, a number of tools have been developed (Fever PAIN score or Centor criteria) to assess the probability of GABHS infection and therefore the need for antibiotic treatment.

Centor criteria	Fever PAIN criteria
History of fever or temperature is > 38°C	Fever (during previous 24 hours)‎
Absence of cough	Purulence (pus on tonsils)‎
Tender anterior cervical lymphadenopathy or lymphadenitis	Attend rapidly (within 3 days after ‎onset of symptoms)‎
Tonsillar swelling or exudate	Severely Inflamed tonsils
	No cough or coryza (inflammation of ‎mucus membranes in the nose)‎

Antibiotic of choice	Penicillin allergy and not pregnant	Penicillin allergy and pregnant
phenoxymethylpenicillin 2 – 4 times/day for 5 – 10 days	Clarithromycin twice a day for 5 days	Erythromycin twice a day for 5 days

Amoxicillin and other Ampicillin antibiotics should be avoided in sore throat due to the possibility of causing maculopapular exanthems in patients with infectious mononucleosis

Infective Mononucleosis

Caused by the Epstein-Barr virus (EBV). Age group 15 – 24 years

Spread mainly through contact with saliva through kissing or sharing food and drink utensils. It can also spread during sexual contact, blood transfusions, organ transplantations, and by intrauterine transmission.

Clinical features: – ‎

• Fever with cervical lymphadenopathy (Lymph nodes are mildly tender and mobile)
• Severe Sore throat, tonsillar enlargement, palatal petechiae ‎are 1 – 2 mm in diameter, and ‎there is usually a ‘whitewash’ exudate on the tonsils.‎
• Other clinical features that may support a diagnosis of glandular fever include:‎
  • Prodromal symptoms — general ‎malaise, fatigue, myalgia and retro-orbital headache.‎
  • Non-specific rash — macular, petechial, urticarial, or erythema multiforme-‎like, or a maculopapular rash that presents after treatment with amoxicillin.‎
  • Splenomegaly — the spleen reaches maximum size at the beginning of the 2^nd ‎week and regresses over 7 – 10 days.
  • Hepatomegaly — mild tenderness in the right ‎hypochondrium.‎

Investigations: –

1. In children < 12 years of age and in people who are immunocompromised at any ‎age — Arrange EBV-serology tests after the person has ‎been ill for at least 7 days.‎
2. In children older than 12 years of age and in immunocompetent adults — Arrange FBC with differential WBCs (lymphocytosis) and a Monospot test in the second week of the illness.‎
   • Glandular fever is likely if the monospot test is positive or the FBC has > 20% atypical or ‘reactive’ lymphocytes, or  >10% atypical lymphocytes and the lymphocyte count is > 50% of the total white cell count. 

Treatment: –

1. Supportive treatment (Symptoms last for 2 – 4 weeks) and airway protection if needed.‎
2. Advise the patient: –
   • Avoiding heavy lifting and contact sports for the 1^st month of the illness (to reduce the risk of splenic rupture).
   • Tiredness is common and is often the last symptom to resolve. ‎
   • Avoiding kissing and sharing eating or drinking utensils
   • Advise the person to seek urgent medical advice if develop new symptoms or symptoms are getting worse‎