Progressive mucocutaneous herpes simplex infection due to acyclovir-resistant virus in an immunocompromised patient: correlation of viral susceptibilities and plasma levels with response to therapy.

Rapidly progressive disease due to acyclovir-resistant herpes simplex has not been described. We report such a case and detail successful patient management using viral sensitivities and plasma acyclovir levels to guide therapy. Response was correlated with plasma levels above those inhibiting viral growth by 50% (ID50) in vitro.