A 16-year-old male presented to the Emergency Department with a painful 3 × 3 cm left-sided neck swelling six hours following blunt trauma to the neck from a heavy swinging door. A CT angiogram was performed which revealed a large haemorrhagic lymph node as well as generalised cervical lymphadenopathy. The patient was eventually diagnosed with infectious mononucleosis. This case report describes a rare case of traumatic haemorrhagic cervical lymphadenopathy with an underlying diagnosis of infectious mononucleosis.