A review of anatomical and immunological links between epidural morphine and herpes simplex labialis in obstetric patients

The anatomical basis for facial itch after epidural morphone is outlined. CNS nuclear events which reactivate latent herpes simplex and immune inhibition resulting in maternal mouth vesicles or neonatal infections are described. Morphine is hypothesized to affect these processes and facial itch is only a marker, not a trigger of this trigeminal opioid activity.