Peter J. Dyck, MD, FAAN, responds:

No cure exists for postherpetic neuralgia caused by shingles, but treatments are available, and for most people the condition resolves or improves with time.

Viral Culprit

Postherpetic neuralgia is a complication of shingles, an infection caused by the herpes zoster virus, which also causes chickenpox. After a childhood case of chickenpox, the virus can remain dormant for years. If it becomes reactivated in adults, it can cause shingles. Postherpetic neuralgia can result from nerve damage that affects the nerve cells, and can cause pain for weeks, months, or, occasionally, years.

Risk Factors

Certain factors such as older age (60 or older), genetics, having diabetes or an especially severe case of shingles, a compromised immune system, or an infection can increase the risk of postherpetic neuralgia. The debilitating pain can also cause fatigue, insomnia, poor appetite, and poor concentration.

Vaccine Option

The US Food and Drug Administration (FDA) has approved a shingles vaccine that can reduce the chance of getting both shingles and postherpetic neuralgia, or reduce the severity if an outbreak does occur. The vaccine is approved for people 50 and older but insurance may not cover the cost until you turn 60. Additionally, a new vaccine may be approved in the coming years that has proved more effective in phase 3 trials than the current vaccine.

Available Treatments

You may be able to avoid postherpetic neuralgia completely by taking an antiviral medication such as acyclovir (Zovirax, Valtrex) or valacyclovir (Valtrex) within three days of a shingles outbreak. Otherwise, treatments include a short course of an anti-inflammatory drug such as prednisone to reduce inflammation within the nerves. The antiseizure medication pregabalin (Lyrica) is approved by the FDA to help reduce pain by stabilizing the electrical-like activity in damaged nerves. Neurologists may also prescribe gabapentin (Neurontin, Gralise, Horizant). Side effects may include drowsiness, sleepiness, and loss of balance. Antidepressants, including escitalopram (Lexapro) or quetiapine (Seroquel), help reduce the pain and treat any associated depression. Side effects may include drowsiness, dry mouth, and sometimes weight gain. If the pain is severe, doctors may prescribe a low-dose of an opioid painkiller such as oxycodone. Opioids can be addictive so you should discuss the risk of addiction with your doctor before you start taking the drugs.

Peter J. Dyck, MD, FAAN, is the Roy E. and Merle Meyer Distinguished Professor of Neuroscience and director of the Peripheral Nerve Research Laboratory at the Mayo Clinic in Rochester, MN.