Synopsis
Recognise Epstein–Barr virus infectious mononucleosis, protect the airway and spleen, distinguish alternative causes of glandular-fever illness and avoid unnecessary antibiotics and unsafe activity.
- The typical syndrome combines fever, pharyngitis, posterior cervical lymphadenopathy and fatigue, but age and immune status alter presentation.
- Examine the airway, hydration, liver and spleen and ask about abdominal pain; tonsillar appearance alone cannot determine severity.
- A heterophile antibody test may be negative early or in younger people. EBV-specific serology clarifies timing when the diagnosis matters and the initial test is non-diagnostic.
Key red flags
Progressive tonsillar swelling, muffled voice, drooling, stridor, inability to swallow or respiratory effort requires urgent airway-capable assessment.
Investigation priorities
Identify lymphocytosis, atypical lymphocytes, cytopenia and an alternative haematological pattern.
Management branches
The patient is stable, drinking and has no airway, hepatic, haematological or abdominal emergency.
- Confirm the clinical pattern, use selective FBC and EBV testing when helpful and avoid antibiotics unless bacterial infection is established.
- Provide fluids, appropriate analgesia, rest and written advice about fatigue, alcohol while liver tests are abnormal and transmission through saliva.
There is stridor, inability to swallow, severe cytopenia, neurological disease, hepatic failure or suspected splenic rupture.
Key medicines
ParacetamolFor most adults give 500 mg to 1 g by mouth at intervals of at least four hours, no more than 4 g daily.
Corticosteroid for selected severe complicationUse a short specialist-directed systemic regimen only for threatened airway or another accepted severe immune complication.