Postherpetic Neuralgia

Overview of Shingles and PHN.

If you have had shingles, you know how painful active shingles can be. But if the intense pain remains or returns after the rash has cleared up, you are probably experiencing nerve pain from postherpetic neuralgia (PHN).

An estimated 10% to 15% of shingles patients develop PHN, a complication of shingles. Your doctor can diagnose you and provide you with treatment options for the immediate pain. However, you should expect a few weeks or months of moderate pain before you start to notice dramatic improvements.

Postherpetic Neuralgia Causes

To help you understand how shingles can cause PHN, you need to know how you can get shingles. Shingles is caused by a viral infection called herpes zoster. The herpes zoster virus typically first shows up as chicken pox during childhood, which means the same virus that causes chicken pox also causes shingles.

For some people who get chicken pox, the virus can lay dormant in nerve cells for years; it can re-activate later as shingles. And this chain of events can lead to PHN.

Researchers aren't exactly sure what triggers the herpes zoster virus to re-emerge after all those years, but they think it is related to age, illness, and stress. Shingles can be very painful, and when the virus reaches the skin, it can cause blistery rashes.These rashes usually heal in less than 3 months. However, if the pain of shingles lingers longer than 3 months, you may have PHN.

During your bout with shingles, the virus you were fighting injured nerves in and around the skin where the rash and blisters once existed. As your immune system eventually suppressed the virus, your rash and blisters disappeared. You may have even felt less pain, and you assumed that you had won the battle with shingles.

However, a few days or weeks later, the nerve damage caused by shingles disrupts the functioning of the nervous system. The damaged nerve sends random, uncontrolled pain signals to the brain, and causes a throbbing, burning sensation along the nerve.

Over time, the confused nerves in your skin will calm. While your body repairs the damaged nerves, your doctor can help you with treatments for the pain. Common pain medications, skin creams, and drug-containing patches are all options that you and your doctor can consider.

In most cases,  the pain will gradually go away. There is a small risk the pain will return intermittently, or be with you for the rest of your life. However, the majority of patients experience no postherpetic neuralgia pain within one year.

Risk factors for developing PHN include:

  • Age: The older you are, the more likely you are to develop postherpetic neuralgia: PHN primarily affects people older than 60 years old. Older people who have shingles have about a 50% chance of developing PHN.
  • Severity of your shingles symptoms: If your shingles symptoms are severe, or if shingles affects your forehead and/or eyes, you're more likely to develop PHN.
  • Other health conditions: People who have suppressed immune systems (eg, people on chemotherapy or people who have HIV or AIDS) are more likely to get PHN.
Updated on: 11/06/15
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