Postherpetic neuralgia is a nerve pain due to damage caused by the varicella zoster virus.Typically, the neuralgia is confined to a dermatomic area of the skin, and follows an outbreak of herpes zoster (commonly known as shingles) in that same dermatomic area.ostherpetic neuralgia is thought to be nerve damage caused by herpes zoster. The damage causes nerves in the affected dermatomic area of the skin to send abnormal electrical signals to the brain. These signals may convey excruciating pain, and may persist or recur for months, years, or for life.