“…Further studies are needed to examine cross‐sensitization. Moreover, it is crucial to establish that no other cross‐reactivity exists, in particular with synthetic products used for general anesthesia, as shown for fentanyl . Fortunately, our patients did not show cross‐sensitization to fentanyl, sufentanil, alfentanil, sufentanil, or tramadol, which can thus be used safely.…”