Skin reaction patterns to the intradermal injection of a whole‐body flea extract were examined in five physically healthy dogs and in 24 dogs with German Shepherd dog Pyoderma (GSP) at 15 and 30 minutes and at 1, 2, 4, 8, 24, 48 and 72 hours after the injection. In 10 out of 24 GSP dogs a positive skin reaction was observed macroscopically after 15 minutes. Delayed reactions at 24 or 48 hours were not observed. In the control group neither immediate nor delayed reactions were observed.