A reference for
patients & their physicians
National Shingles Foundation
Copyright © National Shingles Foundation, Inc.
The National Shingles Foundation does not practice medicine
and no information contained in this booklet is medical advice or
a substitute for the advice of a physician. If you have any of the
conditions or symptoms described in this booklet, you should consult
a physician as soon as possible.
Each year, approximately 1,000,000 individuals
in the United States develop shingles, or herpes zoster,
an often-painful outbreak of rash or blisters on the skin. Approximately
20 percent of these shingles patients, or 200,000 individuals, go
on to suffer from PHN, or post-herpetic neuralgia. PHN
is caused by damage to the nervous system during the shingles infection
that can result in debilitating pain persisting for months or even
years. The pain of PHN may be sharp, burning, throbbing or stabbing.
The skin may be unusually sensitive to even the lightest touch (as
from clothing or bed sheets), to the smallest breeze, and to changes
in temperature (either hot or cold).
To fully understand PHN, one must take a step backactually
two steps backto chickenpoxvaricellaand its
cause, the varicella-zoster virus (VZV).
The varicella-zoster virus first strikes as chickenpox, now
preventable through vaccination. Following an episode of chickenpox,
the virus lies dormant, or asleep, in nerve tissues. However, the
virus can reactivate or reawaken as shingles. The shingles rash usually
occurs in a band on one side of the body, or clustered on one side
of the face. In otherwise healthy individuals, shingles may disappear
without major consequence in two to four weeks. But the risk of complications
from shingleschief among them, PHNincreases with age,
weakened immunity and delay or lack of treatment.
It is the National Shingle Foundations hope that this booklet
will more fully familiarize you with PHN and provide you and your
physician with an update on PHN pain relief therapies.
(1) What is PHN?
PHN (post-herpetic neuralgia) is the name given to the pain
that lingers for months or even years after the rash caused by an
infection called shingles has healed. Shingles is an often-painful
outbreak of rash or blisters on the skin.
(2) What causes shingles and who can get it?
Shingles is caused by a reactivation of the varicella-zoster virus
(VZV), the same virus that causes chickenpox. Anyone who
has had chickenpox can get shingles, although it is most common in
individuals over the age of 50. It is estimated that 10 to 20 percent
of all Americansand 50 percent or more of individuals aged 85
and olderwill experience shingles during their lifetime. Individuals
who have conditions, or are undergoing medical treatments, that weaken
their immune systems are also more likely to develop shingles. These
include: HIV infection; chemotherapy or radiation therapy; corticosteroids;
transplant operations and possibly stress.
(3) How is shingles treated?
One of three oral, antiviral medications are usually prescribed for
shingles: acyclovir, famciclovir and valaciclovir. Early treatment
with one of these drugsideally within 72 hours of the appearance
of the rashcan lessen the duration of shingles and lower the
risk for PHN. If a patient experiences moderate or severe pain during
acute shingles, a physician may prescribe one or more of the pain
management therapies used in the treatment of PHN, which are listed
in the response to question 16.
(4) What causes PHN?
PHN results from injury to the nervous system caused by the varicella-zoster
virus during the shingles infection.
(5) Is PHN the only serious complication of shingles? Where do these
No. PHN is one of several, potential shingles complications. For example,
shingles affecting the eye (ophthalmic shingles) may result in impaired
vision, or temporary or permanent blindness. Other shingles complications
include local muscle weakness, infection of the central nervous system,
bacterial skin infection and scarring.
The location on the body where a complication manifests itself is
usually dependent on where the shingles rash occurred.
(6) Who can get PHN?
PHN can strike any of the nearly one million individuals who develop
shingles annually in the U.S. It is estimated that approximately one
out of five shingles sufferers, or 200,000 individuals, develop PHN
each year, and that half of shingles patients over age 60and
75 percent of those 70 and olderwill experience PHN to some
In addition to advanced age, other factors which increase the likelihood
PHN will strike include: the severity of the shingles rash; the severity
of the acute pain during the rash; and whether the patient had pain
or other abnormal sensations before the shingles rash appeared.
(7) What are the signs and symptoms of PHN?
If an individual, whose shingles rash has healed, experiences significant
pain in the area where the shingles rash occurred, or beyond that
area, it could be PHN. In addition, if touching the skin causes pain,
the patient may be experiencing allodynia, a frequent symptom of PHN.
Allodynia is a condition in which the skin is unusually sensitive
to normally painless stimuli, such as the touch of clothing or a gust
(8) Where does the pain of PHN usually occur?
PHN occurs in either the area, or a portion of the area, where the
shingles rash appeared. The shingles rash usually occurs on either
the trunk, back, chest, head, face, lower part of the spine or neck,
but it also may occur on the limbs.
(9) What does PHN pain feel like?
The pain of PHN may be sharp, burning, throbbing or stabbing. The
skin may be unusually sensitive to even the lightest touch (as from
clothing or bed sheets), to the smallest breeze, and to changes in
temperature (either hot or cold). The pain may be continuous or intermittent.
(10) How long does PHN last? Will it ever go away?
The duration of PHN varies widely. In some patients, it can last for
months or even years. However, for many patients, the pain will lessen
over time. Furthermore, there are a growing number of pain relief
options for PHN that are proving to be effective for many patients.
(11) Is PHN contagious?
PHN is not contagious.
(12) Can PHN cause depression?
The pain of PHN can interfere with a patients daily routines
and quality of life, resulting in depression. If a patient feels depressed
and demoralized, he/she should discuss these feelings with a physician.
(13) What type of physician should be consulted to treat PHN?
If one suspects PHN, a physician should be seen as soon as possible.
The physician may make a referral to a pain specialist, neurologist
or anesthesiologist who has experience in working with PHN patients.
(14) Can PHN be cured?
Currently, PHN cannot be cured. The relief of the pain it causes is
the focus of treatment. However, the effectiveness of treatment for
PHN varies widely among patients.
(15) Can PHN be prevented?
Currently, PHN cannot be prevented in all patients. However, prompt
medical treatment for shingles can lessen the duration of shingles
and lower the risk for PHN. Specifically, the effectiveness of antiviral
medication (acyclovir, famciclovir or valaciclovir) is well-established
if it is taken within 72 hours after the appearance of the shingles
There is a major study underway The Shingles Prevention
Study whose aim is to determine if vaccination can decrease
the incidence and/or severity of shingles and its complications in
older adults. The study is also trying to determine if vaccination
can protect against PHN. The outcome of this study will help scientists
determine whether PHN prevention is a valid strategy using this vaccine.
(16) How is PHN treated?
The following is a brief summary of PHN treatments and their relative
effectiveness as assessed in a paper published in the May 2000 edition
of the journal Drugs, entitled, "Treatment of Postherpetic Neuralgia:
An Update."1 In this article, authors Ghassan E. Kanazi, M.D.,
Robert W. Johnson, MB, BS, FRCA, and Robert H. Dworkin, Ph.D., reviewed
the findings of recent studies.
Each pain relief medication or procedure assessed is referenced. Reference
is also made to studies conducted on other medications that fall under
the same classes of drugs, but that were unable to be included in
this text due to space limitations. All study references are provided
so that physicians can learn more about each treatment, including
potential side effects.
Ones physician, who is most familiar with an individuals
case of PHN, will be able to determine which of these or other treatments
can best relieve an individuals PHN-related pain. Please note
that the opinions expressed are those of the articles authors
and not the VZV Research Foundation, which is not licensed to practice
I. Pharmacological Approaches
(A) Topical Agents
Topical agents include the lidocaine patch (Lidoderm),
a patch containing a solution of lidocaine, which is the same medication
used by dentists. The lidocaine patch was approved by the U.S. Food
and Drug Administration (FDA) in 1999 to treat PHN.
In their article in the journal Drugs, Drs. Kanazi, Johnson
and Dworkin cite studies that found "a majority of patients treated
reported moderate or greater pain relief."
Capsaicin cream is sold as a pain reliever for arthritis and
PHN. Drs. Kanazi, Johnson and Dworkin stated, in their article, that
capsaicin cream "continues to play a minor role in the treatment
of patients with PHN. Compliance
is low because of the intense
burning after application, which may, however, lessen with time."
1 These authors also reported a recent review concluded there
is no evidence of significant improvement following capsaicin treatment.
- Scientific articles covering other topical agents: 1,5,6,7
(B) Oral Medications
In their article, Drs. Kanazi, Johnson and Dworkin stated that tricyclic
antidepressants (TCA) are the only type of antidepressantsdrugs
which are used to treat depressionthat have been shown to be
effective in managing the pain of PHN. 1 According to these
authors, the TCAs include nortriptyline (e.g. Pamelor),
which has been found to have a significant analgesic effect in treating
PHN pain, and has "fewer (adverse) side effects than amitriptyline,
(the TCA which) has been the most widely used antidepressant in the
treatment of PHN." 1,8
- Scientific articles covering other antidepressants: 1,9,10,11
Anticonvulsants, which were originally designed to prevent seizures
in patients with epilepsy, include gabapentin (Neurontin).
Drs. Kanazi, Johnson and Dworkin make reference, in their article,
to a study which found gabapentin "significantly reduced (PHN)
pain" and resulted in "improvements in sleep, mood and quality
of life." 1,12
- Scientific articles covering other anticonvulsants: 1,13,14
The article by Drs. Kanazi, Johnson and Dworkin notes the controlled-release
opioid analgesics include controlled-release oxycodone (OxyContin),
which, a study found, provides "significantly greater (PHN) pain
relief, reduction of allodynia, decreased disability
receiving placebo." 1,15
- Scientific articles covering other analgesics: 1,16
Ketamine and N-methyl-D-aspartate (NMDA) Receptor
In their article, Drs. Kanazi, Johnson and Dworkin reported recent
studies have shown NMDA receptor antagonists provide some pain relief,
but some may have adverse effects. 1,17,18,19,20
(C) Nerve Blocks
The article by Drs. Kanazi, Johnson and Dworkin cites
a review of several studies, which found "the use of sympathetic
may be effective in relieving pain during acute
shingles, (however) these blocks do not appear to provide prolonged
relief in patients with longstanding PHN. (Therefore) it has been
suggested their use be limited to special occasions where short-term
relief is an important treatment goal." 1,21
II. Physical Treatments
In their article, Drs. Kanazi, Johnson and Dworkin note
the use of natural fiber clothing, rather than artificial fibers,
may help reduce the skin sensitivity (allodynia) often caused by PHN.
1 The authors report that: Transcutaneous Electrical Nerve Stimulation
(TENS) has been "occassionally helpful" 1,22,
but one study reported no benefit. 1,23; ultrasound
"has a poor record in a few small series of patients with PHN"
1,24,25; and acupuncture "
seems to provide
little benefit in PHN." 1,26 The authors also state that
cold packs "often provide short term relief and are always
worth trying." 1
III. Psychosocial Interventions
Drs. Kanazi, Johnson and Dworkin write, in their article,
that cognitive-behavioral therapy, "
specific interventions as relaxation training, biofeedback
and hypnosis, has a well-established role in the treatment
of patients with chronic pain. 1,27,28 Although no studies
have been reported that have specifically examined this
(for) PHN, there is no reason to doubt cognitive-behavioral therapy
provides as significant a benefit in PHN as it does in
chronic pain syndromes
IV. Neuroinvasive Measures
In their article, Drs. Kanazi, Johnson and Dworkin cite
a comprehensive review that was conducted of studies evaluating surgical
procedures used for the treatment of PHN, including skin excision,
dorsal root entry zone lesions, cordotomy and spinal cord
and deep brain stimulation. 1,29 Drs. Kanazi, Johnson
and Dworkin noted these studies "examined a small number of patients
have been controlled, and the duration of patient follow-up has often
been inadequate. Although some surgical procedures may provide significant
relief for a small number of patients with PHN, these procedures are
not without risk and are seldom recommended for the treatment of PHN."
Unfortunately, PHN cannot be prevented or cured
least, not yet. The good news is twofold: (1) over time, the pain
usually lessens; and (2) there are new, emerging pain relief therapies
that appear to be helping greater numbers of patients.
The purpose of this text is to educate you and your physician about
PHN and new research into PHN pain relief therapies. Please note,
however, that the National Shingles Foundation does not practice medicine
and no information contained in this text is medical advice or a substitute
for the advice of a physician. If you have any of the conditions or
symptoms described in this text, you should consult a physician as
soon as possible.
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