Shingles is a painful rash of fluid-filled blisters that is caused by reactivation of the varicella-zoster virus, the virus that causes chickenpox. The varicella-zoster virus is a member of the herpesvirus family (herpesvirus type 3). Shingles is sometimes called herpes zoster. Some people who have had shingles continue to have pain long after the rash has gone away. Such pain is called postherpetic neuralgia, which means nerve pain after herpes.
Exactly why postherpetic neuralgia occurs is not well-understood.
Postherpetic neuralgia occurs most often in older people. As people age, the chance of developing postherpetic neuralgia increases.
Although a number of treatments for severe postherpetic neuralgia have been tried, no treatment is routinely successful.
Postherpetic neuralgia treatments may include
Certain antiseizure drugs (such as gabapentin and pregabalin)
Certain antidepressants (such as amitriptyline)
Topical lidocaine ointment
Botulinum toxin A injected into the affected area, which may reduce the pain