In the cases reported of recall urticaria, the clinical manifestations
usually develop within an hour. We present the clinical case of an 11
-year-old boy who, after 9 weeks of immunotherapy with pollen extracts
(Phleum pratense and Festuca elatior), presented an urticarial lesion
48 to 72 h after of the injection on the opposite arm to where it had
been applied and in the same place where the previous injections had
been administered This reaction continued for every injection given du
ring the time that the immunotherapy was applied twice a week, and for
the 6 weeks that it was applied once a week. Subsequently, the urtica
rial lesions appeared every two or three injections.