A case of herpes zoster peripheral polyneuropathy manifested by foot drop in chronic myeloid leukemia.

In herpes zoster infection, neurological complications may be overlooked because pain is a more prominent symptom and because peripheral polyneuropathy associated with weakness is rare. A 57-year-old male visited our hospital, complaining of pain and skin eruptions on the right flank. He was diagnosed as having herpes zoster and the symptoms were alleviated by administration of acyclovir for a week. After three weeks, the herpes zoster relapsed. He was re-admitted and diagnosed with chronic myeloid leukemia (CML), and imatinib mesylate was prescribed for five weeks. Ten weeks after the onset of herpes zoster, bilateral foot drops and numbness of the right foot dorsum developed. Through an electrodiagnostic study, he was diagnosed as having peripheral polyneuropathy that was suspected to be caused by neural invasion by varicella zoster virus. After administration of famciclovir, not only the pain but also the neurologic symptoms improved. We herein report a case of peripheral polyneuropathy that was supposed to be related to herpes zoster.