What is Shingles?
What is Postherpetic Neuralgia?
What Causes Shingles and Postherpetic Neuralgia?
Can You Prevent Postherpetic Neuralgia?
Who Gets Shingles and Postherpetic Neuralgia?
Pain from Shingles and Postherpetic Neuralgia
Diagnosing Postherpetic Neuralgia
Treatment for Shingles
Recommended Treatments for Postherpetic Neuralgia
Shingles and PHN Websites
More Information on Pain Treatment
The medical term for shingles is acute herpes zoster.
Shingles is a skin rash that develops on half of the body, in a belt-like
pattern. The rash is usually on either the right or left side of the chest,
starting in the middle of the back and wrapping around to the breast --
but it can occur on any part of the body, such as the forehead and abdomen.
Most
of the time, shingles is very painful. Sometimes the pain from shingles
starts several days before the rash appears. When the pain starts before
the skin rash, it can be very hard for doctors to make the correct diagnosis.
Many patients have been told they have heart attacks, appendicitis,
and migraine headaches before getting the correct diagnosis of shingles.
Fortunately, in most cases the pain of shingles gradually disappears
over several weeks or months. Most people with shingles will have no
pain or just a little pain one year after the rash.
If the pain from shingles does not go away, it is called postherpetic
neuralgia (PHN). Only a small number of people with shingles develop PHN.
Many people get chicken pox when they are children
or even when they get older. Chicken pox is caused by the varicella zoster
virus, a herpes type of virus. After the chicken pox heals, the varicella
zoster virus moves from the skin along the nerves and into an area called
the dorsal root ganglia, a part of the nerves
which lie next to the spinal cord. The virus stays there for many years
in an inactive state.
The virus is usually inactive for decades. It can "wake up,"
become active again and multiply when a person's immune system becomes
weakened. For most people who get shingles, the weakening of the immune
system is not the result of a serious problem. It is true that shingles
may be brought on by cancer, AIDS, or drugs that lower the immune system,
but this happens in a very small group of patients. The most common reason
for lowered immunity in shingles patients is being elderly and experiencing
a stressful event, such as an illness in the family or emotional distress.
The reactivated virus begins to multiply within the dorsal root ganglia,
which causes damage and swelling to this area of the nerve. This damage
to the nerve causes the first pains of shingles. The virus then moves
along the nerve to the skin, damaging the nerve and causing swelling as
it goes. When the virus finally reaches the skin, it causes the shingles
rash.
Scientists have not found a treatment that prevents all patients
with shingles from developing PHN. However, there are several treatments
that some think might reduce the chances of developing PHN. These treatments
are:
Antiviral Medication (such
as acyclovir, valacyclovir or famciclovir): These medications kill the
herpes virus during the shingles phase. Studies have shown that they shorten
the time and pain of shingles. Because of this, antiviral medications
probably reduce the chances of developing PHN after shingles, but this
has never been totally proved.
Nerve Blocks: Nerve blocks
are injections of numbing medications, called local anesthetics, into
different nerves. Some doctors believe that doing several nerve blocks
during the shingles phase will stop patients from developing PHN. Unfortunately,
no studies have proven this. Nerve blocks may be a good treatment for
the pain of shingles but should not be given to patients as a treatment
to prevent PHN.
Tricyclic Antidepressants:
One scientific study reported that giving the antidepressant amitriptyline
(Elavil) during the shingles phase reduced the chance of developing PHN.
Scientists need to do another study like this, with the same results,
before everyone with shingles is given this type of medication.
Herbs and Other Medicinals:
Many patients visit their doctors and ask about cures or treatments they
have heard about in medical magazines, on the Internet, or from friends
or relatives. Doctors might discourage their patients from using some
of these treatments if there could be any harmful effects. Patients should
not expect that any of these treatments will prevent them from getting
PHN -- the sad fact remains that no treatment given during the shingles
has been shown in scientific studies to prevent PHN.
For more information on complementary therapies for PHN, please visit
our pages on
HealingChronicPain.org.
Age is an important factor in determining who gets shingles and PHN. The
older you are, the greater chance you have of developing shingles. And,
the older you are when you get shingles, the greater chance you have of
developing PHN.
Recently, a good scientific study showed that older people with a neuropathy
(nerves of the body that are not working correctly, usually due to old
age or diabetes) are more likely to develop PHN after shingles. It is
interesting that most people in this study who had a neuropathy before
they got shingles did not know they had a neuropathy -- they did not
have any symptoms. Therefore, having a neuropathy, even if it is not
causing symptoms, may increase the chances of getting PHN.
Other studies have suggested that the more severe and painful the shingles
rash is, the greater the chance of long-lasting PHN pain. Also, some
studies have concluded that people who do not cope well with stress
and pain may have worse PHN than others who cope better.
Patients often describe the pain from shingles as a horrible, unbearable
pain in the area of the rash. Each patient may experience different types
and degrees of pain. The words used to describe the pain include sharp,
electric-like jabs, burning, throbbing, aching, and skin sensitivity.
Most patients who develop the chronic pain of PHN say that the pain is
less severe than the shingles pain, but it may still be intense. Like
shingles pain, the pain of PHN can be described as sharp, electric-like
jabs, burning, throbbing, aching, and skin sensitivity, and the pain is
different from patient to patient. Patients might also have intense itching
in the painful area. The pain of PHN may spread beyond the original shingles
rash, and often includes several inches above the rash area. Some patients
have severe skin sensitivity (called allodynia)
that can be very disabling, especially if the sensitive area is on the
chest, trunk, or limbs, making the touch of clothing unbearable.
People suffering from shingles or PHN may develop depression, anxiety,
and sleeping difficulties because of the severe pain. The patient should
tell his or her doctor about these problems so they may be treated.
Also, some patients describe a "sagging of the muscles" in the
area of the shingles. When doctors examine the region, a loss of muscle
tone is seen. This might be caused by damage of some nerves that control
the muscle tone in the area of the shingles.
PHN is simple for a doctor to diagnose, without any laboratory testing.
Any patient who develops a chronic pain at the site of the shingles rash
has PHN. The area of pain of PHN may be smaller than the shingles rash
or may spread several inches larger than the shingles rash.
Antiviral Medication (such
as acyclovir, valacyclovir, and famciclovir): For most patients with shingles,
oral antiviral medication should be prescribed for 7 days. The earlier
this medication is taken, the better the chance of stopping the virus
from causing more damage to the nerves. Early treatment with antiviral
medication can lessen the intensity and duration of shingles pain (but,
as mentioned above, there is no definite proof that these medications
will stop the patient from getting PHN). Once the rash has healed, the
patient should stop taking antiviral medication.
Steroids(such as prednisone):
Some studies have shown that early treatment with a short course (usually
1-2 weeks) of steroids can decrease the intensity and duration of pain
associated with acute shingles.
Nerve Blocks: Pain specialists
can inject numbing medications (called local anesthetics)
directly into certain nerves to help with shingles pain. As mentioned
above, these nerve blocks have not been proven to reduce the chances of
developing PHN, but nerve blocks may provide good temporary pain relief
for the shingles.
Opioid Medication (narcotics):
Opioid medications, such as morphine, oxycodone, codeine, hydromorphone,
and methadone, can provide good pain relief without side effects for many
patients. In most cases, there should be no concern about developing "addiction"
when these drugs are used to treat the severe pain of shingles. Patients
can be safely taken off of the narcotic medication if it is no longer
needed.
Tricyclic Antidepressants
(such as amitriptyline [Elavil] and nortriptyline [Pamelor]): One study
has shown that giving tricyclic antidepressants during the early shingles
phase can help reduce the pain and help reduce the chance of developing
chronic PHN pain. When used in this way, tricyclic antidepressants are
not given to treat any kind of depression -- they are prescribed for pain
relief and perhaps to reduce the chance of getting PHN.
There is good and bad news about treating PHN. The bad news is that
there are no treatments that reverse the nerve damage caused by shingles,
and there are no treatments that can improve the healing of the nerves.
The good news is that there are many different treatments available for
the pain of PHN. Some treatments work better for some patients than for
others, and some cause bad side effects in some patients but no side effects
in others. So each patient with PHN should be tried on a variety of medications
until the drug or combination of drugs is found that gives good pain relief
with no or little side effects.
VIDEO:
Drug Therapy for Neuropathic Pain in the Medically Ill
It is very important that doctors start all oral medications (that is,
medications taken by mouth in pill, tablet or syrup form) at a low dose
and then gradually increase the dose until pain is relieved or side effects
occur. This gradual increase in dosage, called "titration,"
is important because every patient with PHN is different and each may
respond to a different dose of each medication.
Topical Lidocaine Patch:
This is a new medication that can be used to treat the pain of PHN and
other conditions. As many as 3 patches (each about the size of an adult
hand) can be placed directly over the painful area of the skin. The patches
are applied for at least 12 hours on the skin. They may be removed from
the skin for 12 hours per day. The medication is believed to act locally.
Within 1-2 weeks, most patients begin to notice relief.
Anticonvulsants (such as
gabapentin [Neurontin] and carbamazepine [Tegretol]): Drugs used to treat
epilepsy and seizures have been used for many years to help relieve the
pain of PHN. In recent years, the antiseizure drug gabapentin (Neurontin)
has become available, and it is widely prescribed for PHN by pain specialists
today (often as the first medication tried). It has been shown in a large
study to be effective and safe for many patients with PHN, with few side
effects. Also, gabapentin does not interact with any other medication,
making it a good choice for many patients who are taking several different
medications at once.
Pregabalin (marketed as LyricaŽ) was approved by the US Food and Drug Administration (FDA) in December 2004 for the treatment of neuropathic pain in
people with diabetes and shingles. The most common side effects associated with Pregabalin include dizziness and sleepiness.
Carbamazepine (Tegretol) is an older antiepilepsy drug that has been used
for PHN pain. This medication helps some patients, but many others complain
of side effects, such as mental changes and dizziness. Patients taking
this drug need regular blood tests.
Many other anticonvulsant medications are available, and doctors may try
using others to treat PHN.
Tricyclic Antidepressants
(such as amitryptiline [Elavil], nortriptyline [Pamelor], desipramine,
doxepin): Up until the past year or so, tricyclic antidepressants (TCAs)
were probably the most widely used medicines to treat the pain of PHN.
Many studies have shown that some patients with PHN have good pain relief
from these drugs. However, many patients also complain of side effects,
such as severe dry mouth, constipation, sedation, trouble thinking, and
dizziness.
Newer antidepressant drugs, such as fluoxetine (Prozac), paroxetine (Paxil),
and sertraline (Zoloft), might be helpful for some patients with PHN.
These medications usually have less side effects than the tricyclic antidepressants,
but studies have found that they are generally less effective for pain.
Opioids (such as oxycodone,
morphine, methadone): For some patients, opioid medications greatly relieve
the pain of PHN without serious side effects. When using these drugs as
the main pain medication, it is important that the doses be given "around-the-clock"
to keep a certain amount of the drug in the bloodstream.
The use of opioid medications for chronic pain continues to be controversial.
Pain specialists now agree, however, that some patients greatly benefit
from taking opioids. When used properly, the drugs can be taken long-term
for pain management with few side effects. A physician would do a risk assessment
for the potential for addiction whenever he or she prescribes opioids. The risk of
addiction is likely to be very small in the large population without a
prior history, or a family history, of addiction. The risk is understood
to vary across populations, and the physician needs to stratify risk by
evaluating risk factors such as this history. Careful dose reduction by the physician, and
co-administration of other drugs, can allow discontinuation of an opioid
without acute withdrawal in most patients.
Nondrug Therapies: Like other
kinds of patients with chronic pain, patients with PHN may benefit from
many non drug treatments. These include rehabilitation therapies and psychological
therapies (such as relaxation therapy and biofeedback). Also, patients
may get pain relief from therapies that stimulate the nerves, such as
TENS (Trancutaneous Electrical Nerve Stimulation). TENS units are small
devices that send very small amounts of electrical current to the skin
through electrodes that are stuck to the skin.
Practice Guidelines: Treatment of Postherpetic Neuralgia (AHRQ)
What Measures Relieve Postherpetic Neuralgia? (.pdf) - The Journal
of Family Practice
National Institutes of Health: Medline Plus
AfterShingles.com
VZV Research Foundation
See our
Treatments or
Mind-Body pages.
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