Slideshows Images Quizzes
font size

Postherpetic Neuralgia (PHN)

Medical Author:
Medical Editor:

Postherpetic neuralgia (PHN) facts

  • PHN is a painful complication that occurs after a shingles infection.
  • PHN is caused by viral damage to nerve cells.
  • PHN is diagnosed by the patient's history and physical exam.
  • Treatment often requires more than one agent to reduce pain.
  • PHN may last one to two months, but some patients have PHN for longer than a year.
  • Older people and people with relatives who get shingles are at a higher risk for PHN.
  • Complications of PHN may include severe pain, pain-medicine addiction, diminished lifestyle, and in a few patients, paralysis of the affected area.
  • The prognosis of PHN ranges from good to poor, depending on the length of time the disease lingers and on the development of complications.
  • PHN can be prevented in many people by a vaccine designed to prevent shingles (Zostavax).

What is postherpetic neuralgia (PHN)?

Postherpetic neuralgia (also termed PHN) is a condition of recurring or persistent pain in an area of the body that has undergone an outbreak of herpes zoster virus (HZ), also known as the varicella zoster virus, commonly termed shingles. It usually begins after shingles lesions (blisters) begin to crust over and heal but may occur in some patients who do not produce lesions. Some investigators suggest the pain has to be present for three months to be termed PHN.

What causes postherpetic neuralgia?

Postherpetic neuralgia is thought to be caused by the damage or alteration of nerves that register pain, pressure, and other sensory nerves (for example, touch) that occur when the reactivated HZ viruses travel down nerves to the skin. This process first begins when the virus causes chickenpox in an individual; the viruses can infect various dorsal root ganglia (nerve cells) as the chickenpox subsides. These viruses then can be reactivated, usually decades later, and produce shingles lesions. The reactivation of HZ is thought to be due to a stress on the body from either another infection or a immunocompromised state (for example, some patients undergoing treatments for leukemia) that allows the HZ to escape the dorsal root cells. PHN does not occur in everyone who gets shingles; about 9%-14% have symptoms after one month post-shingles and about 5% have PHN three months post-shingles.

Medically Reviewed by a Doctor on 8/23/2016


Women's Health

Find out what women really need.

Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations

Health Solutions From Our Sponsors