[Fentanyl induced intraoperative anaphylactic reaction].

We report a case of intraoperative fentanyl anaphylactic reaction. The patient was a previously healthy 12-year-old boy with severe head injury by a traffic accident. We experienced a rapid hemodynamic change after fentanyl injection and that occurred again after another fentanyl injection. In the second hemodynamic change, red wheals appeared on the skin. We clinically diagnosed this as fentanyl anaphylactic reaction. Six weeks later we performed prick test and intradermal test, but the patient had negative results for fentanyl in both tests. Although it is rare that opioids cause anaphylactic reaction, we must differentiate them when we search causative agents. Even if skin tests are negative, there is a possibility of false negative reactions. Therefore it is safe to regard suspicious agents as causative agents in cases where the agents are clinically suspected.