A Rare Case of Yellow Urticaria Developing During Blood Transfusion.

Yellow urticaria is a rare clinical variant of urticaria characterized by yellowish wheals, typically associated with hyperbilirubinemia. Its occurrence as a transfusion-related reaction is uncommon and may mimic more serious transfusion complications. We report the case of a 15-year-old Saudi female patient who presented with prolonged vaginal bleeding and severe iron deficiency anemia requiring packed red blood cell transfusion. Approximately 15 minutes after transfusion initiation, she developed pruritic yellowish urticarial wheals over the trunk and extremities, without angioedema or hemodynamic instability. Laboratory evaluation revealed mild hyperbilirubinemia, while direct and indirect Coombs tests were negative, and no clinical or laboratory evidence suggestive of hemolysis was identified. The transfusion was temporarily interrupted, and the patient was treated with antihistamines, corticosteroids, and epinephrine, leading to complete resolution of the lesions within 24 hours. Transfusion was later resumed without recurrence. This case highlights transfusion-related yellow urticaria as a benign but rare reaction. Early recognition is essential to avoid misdiagnosis and unnecessary interruption of life-saving transfusion therapy.