Postherpetic neuralgia is chronic pain in areas of skin supplied by nerves infected with herpes zoster (shingles).
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, so 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 the painpostherpetic neuralgia occurs is not well-understood. However, it does not indicate that the virus is actively reproducing (replicating).
Postherpetic neuralgia occurs most often in older people: 25 to 50% of people who are older than 50 years and who have had shingles also have postherpetic neuralgia. However, only about 10% of people with shingles develop postherpetic neuralgia.
The pain may be constant or intermittent, and it may worsen at night or in response to heat or cold. Few people have severe pain. But sometimes the pain is incapacitating.
In most instances, the pain subsides within 1 to 3 months. But in 10 to 20% of people, the pain persists for more than 1 year. It rarely persists more than 10 years.
If people who have had shingles continue to have pain in the area affected by shingles, they should see a doctor right away because treatment must be started early to be effective.
Postherpetic neuralgia diagnosis is usually based on symptoms and results of a physical examination in people who have had shingles.
Mild pain requires no specific treatment other than nonprescription pain-relieving drugs (such as acetaminophen) or creams (such as capsaicin).
Although a number of treatments for severe postherpetic neuralgia have been tried, no treatment is routinely successful.
Postherpetic neuralgia treatments may include
Certain anticonvulsants (such as gabapentin and pregabalin)
Certain antidepressants (such as amitriptyline)
Topical lidocaine ointment
Rarely, injection of a corticosteroid into the cerebrospinal fluid (in the space around the spinal cord), which may be helpful
Injecting botulinum toxin A into the affected area, which may reduce the pain