Postherpetic neuralgia is a painful condition affecting your nerve fibers and skin. It's a complication of shingles, a second outbreak of the varicella-zoster virus, which initially causes chickenpox.

During an initial infection of chickenpox, some of the chickenpox virus can remain in your system, lying dormant inside nerve cells. Years later, factors such as age, illness, stress or medications can reactivate the virus. It can also reactivate for no apparent reason.

Once reactivated, the virus travels along nerve fibers, causing pain. When the virus reaches the skin, it produces a rash and blisters, known as shingles (herpes zoster). A case of shingles usually heals within a month. But some people continue to feel pain long after the rash and blisters heal. This pain is known as postherpetic neuralgia.

Not everyone who develops shingles develops postherpetic neuralgia. But this condition is a common complication of shingles in older adults. The greater your age when you develop shingles, the greater the chance you'll develop postherpetic neuralgia.

There's no cure for postherpetic neuralgia. But in most people, the condition lessens over time. In the meantime, symptoms - especially if addressed early - can be eased with treatments that relieve nerve-related pain.

Signs and symptoms

The symptoms of postherpetic neuralgia are generally limited to the area of your skin where the shingles outbreak first occurred. They may include:

• Sharp and jabbing, burning, or deep and aching pain

• Extreme sensitivity to touch and temperature change

• Itching and numbness

In rare cases, you might also experience muscle weakness, tremor or paralysis — if the nerves involved also control muscle movement.

Causes

Postherpetic neuralgia results when nerve fibers are damaged during a case of shingles. Damaged fibers aren't able to send messages from your skin to your brain as they normally do. Instead, the messages become confused and exaggerated, causing chronic, often excruciating pain that may persist for months — or even years — in the area where shingles first occurred.