Postherpetic Neuralgia

What is postherpetic neuralgia?

Postherpetic neuralgia is pain that you keep having from shingles long after the shingles rash has healed.

Shingles is an infection of the nerves caused by the varicella-zoster virus, which is the same virus that causes chickenpox. When this virus causes shingles it is called herpes zoster.

How does it occur?

If you have had chickenpox, you are at risk for later developing shingles. After you recover from chickenpox, the chickenpox virus stays in your body. It moves to the roots of your nerve cells (near the spinal cord) and becomes inactive (dormant). Later, if your immune system gets weak or very stressed—for example, by illness, some medicines, or just normal aging—the virus can become active again. Instead of causing chickenpox again, it causes shingles.

For most people the pain caused by shingles fades away in the first month or two after the blisters heal. If the virus damages a nerve, you may have pain, numbness, or tingling for months or even years after the rash is healed. If you keep having pain for more than 4 months after the blisters heal, you have postherpetic neuralgia.

Postherpetic neuralgia is most likely to occur after a shingles outbreak if you are over 50. The worse the rash is while you have shingles, the more likely it is that the pain will be severe and long-lasting.

What are the symptoms?

The main symptom is pain in the area where you previously had the shingles rash. The pain may be stabbing, aching, or burning. It may come and go, or it may be constant. Some people can become overwhelmed and depressed by having to cope with pain every day.

Postherpetic neuralgia may also result in:

• tiredness
• loss of appetite
• inability to perform your usual daily tasks because of the pain.

How is it diagnosed?

There are no special tests for postherpetic neuralgia. Your healthcare provider will ask about your pain and if you have ever had chickenpox or shingles.

How is it treated?

A variety of treatments have been tried to ease the pain of postherpetic neuralgia. What helps one person may not help another. If a treatment does not work, tell your healthcare provider.

Your provider may prescribe:

• an anesthetic cream to put on the painful area (such as EMLA cream or capsaicin cream)
• medicines you take by mouth, such as:
  • acetaminophen
  • narcotic pain relievers
  • antidepressants (especially older tricyclic antidepressants)
  • anticonvulsant medicine, such as divalproex, gabapentin, and pregabalin
• cold packs
• time-release anesthetic patches

If the postherpetic neuralgia is very bothersome and medicines aren’t helping, you and your healthcare provider may consider one or more procedures, such as:

• Nerve blocks: Your healthcare provider injects long-lasting pain medicine into or next to the nerve causing the pain.
• Nerve destruction, or ablation. Your provider destroys the nerve with a microwave probe.
• Intrathecal injections: Your healthcare provider injects a mix of steroid and anesthetic medicines into the fluid in your spine. Although this did work well in a couple of studies from Japan, it has not been studied and is not done often in the United States.
• Spinal cord stimulation: A thin electrical probe is placed into the spinal canal and stimulates the spinal cord. In small studies, the stimulation controls the neuralgia pain. This technique is done only in advanced neuroscience centers and is not well proven or widely available.
• Deep brain stimulation: A thin electrical probe is implanted in the brain to stimulate centers that control pain perception. This technique is done only in advanced neuroscience centers and is not well proven or widely available.

How long will the effects last?

Most people have 3 to 6 weeks of pain and then it fades away, but the pain can last for months to years.

How can I take care of myself?

You may find the following helpful:

• Take all medicines as directed by your healthcare provider.
• Let your provider know what in your treatment plan works and what doesn't.
• To keep your immune system strong, eat a healthy diet that is low in saturated fats and includes fruits and vegetables.
• Get enough sleep.
• Get 20 to 30 minutes of aerobic exercise (such as walking or swimming) every day.
• If you are feeling emotionally overwhelmed by the pain, let your provider know. You may want to look for a local chronic pain support group.

How can I help prevent postherpetic neuralgia?

For prevention of shingles, a vaccine called Zostavax is now available for people 60 years of age and older. This shot helps prevent or lessen the symptoms of shingles. It cannot be used to treat shingles once you have it.

For rapid treatment of shingles, tell your healthcare provider right away if you think you have shingles. If you start taking an antiviral medicine (such as acyclovir) within the first 3 days of the rash, you may be able to avoid some or all of the postherpetic pain. Some experts believe that antiviral medicines started within 7 days of the rash in people over age 55 may prevent postherpetic pain.

Some healthcare providers may prescribe corticosteroids such as prednisone to prevent the development of postherpetic neuralgia as well as to control the pain of shingles. However, researchers who have studied this treatment say that it does not work and probably is not worth the risk of steroid side effects.

One study showed good reduction in the risk of getting long-lasting pain by starting amitriptyline as soon as shingles started. This medicine treats the pain directly, not the virus.