[Findings of blood examinations before posttransfusion urticaria].

Background: Although the occurrence of posttransfusion urticaria in the immunosuppressive period is believed to be rare, from our experiences, this disease develops regardless of the immune status of the patients. Therefore, we performed a retrospective study to determine whether posttransfusion urticaria develops during the period of bone marrow suppression.

Methods: This study included 20 patients who developed urticaria as a complication of blood transfusion from January 2010 to January 2011 at the Department of Pediatrics, Hiroshima University Hospital. We retrospectively analyzed the patients' the blood examination data obtained before blood transfusion to elucidate the mechanism underlying posttransfusion urticaria.

Results: White blood cell counts were low before the patients developed urticaria; particularly, neutrophil counts were significantly low. Furthermore, the monocyte, eosinophil, and basophil counts were significantly lower before the development of urticaria.

Discussion: Urticaria tends to develop in a condition of neutropenia. Thus, care must be taken to prevent the development of this disease during the neutropenia period.