What causes postherpetic neuralgia?

Postherpetic neuralgia is a nerve pain that occurs at the site of a previous attack of a condition called shingles. Neuralgia is a term that describes nerve pain.

Postherpetic neuralgia is nerve pain which continues 3-6 months after the shingles rash has healed.

Shingles is a condition caused by re-activation of the varicella-zoster virus, which lies dormant (inactive) in the nerves following a chickenpox infection. The virus becomes active in two or three nerve roots and causes a flu-like illness. In most cases, the rash and pain of shingles lasts two to four weeks.

The pain of postherpetic neuralgia may be intense and can take the form of:

# burning

# stabbing

# aching

# itching

# an ‘electric shock’

# hyper-sensitivity of the skin in the affected area (allodynia)

It is important to revisit your GP if you continue to have pain for more than two or three months after having shingles. The earlier the diagnosis is made, the greater the chance of relieving the pain of postherpetic neuralgia.

Postherpetic neuralgia is easy to diagnose because it only occurs as a complication of shingles, and the pain will be in the area of the body supplied by the affected nerves.

If you have had shingles, your GP can diagnose postherpetic neuralgia based on your symptoms and the length of time you have had them.

Who is affected?

Approximately 10-20% of people with shingles will go on to develop postherpetic neuralgia. The risk of developing postherpetic neuralgia increases with age. It is more common in people over 60 and affects one-third of people over 80.

Treating postherpetic neuralgia

Many people with postherpetic neuralgia make a full recovery within a year of developing the condition. But occasionally, the nerves do not heal completely and symptoms last for several years or permanently.

Treatments can ease the symptoms of postherpetic neuralgia, although they may not relieve the pain completely.

Most people respond to medication, such as tricyclic antidepressants, anti-epileptic or opioid pain medication, which can be prescribed to reduce the pain.

About 40-50% of people with postherpetic neuralgia do not completely respond to any form of treatment.

A vaccine is available for people over 50 to boost immunity and prevent reactivation of the virus. This has been shown to reduce considerably the likelihood of getting shingles for at least five years. It may need to be repeated for lasting immunity.

Living with long-term pain

Living with postherpetic neuralgia can be very difficult. Postherpetic neuralgia can interfere with your ability to carry out certain daily activities, such as dressing and bathing. You may also have problems sleeping and feel tired (mental or physical tiredness) which can lead to stress and anxiety.

Living with pain, particularly if it affects your quality of life, can also lead to depression (feelings of extreme sadness or despair that last for a long time).