<p>A bruise or haematoma in a non-mobile infant is a red flag prompting concern for non-accidental injury. Bruising does not always signify trauma however and may occur spontaneously due to an underlying medical cause. This case report describes a 3-month-old infant presenting with unexplained faint bruising to the axilla and an associated lump. Point of care ultrasound revealed a chest wall haematoma without any other evidence of trauma prompting blood tests, which demonstrated severely deranged coagulation and conjugated hyperbilirubinaemia. The child was subsequently diagnosed with Alagille Syndrome. Point of care ultrasound is a useful clinical adjunct for providing greater detail to the examination of unusual lumps or swellings which in this case prompted further investigations leading to a rare diagnosis.</p>