Postherpetic Neuralgia

What is Postherpetic Neuralgia?

Postherpetic neuralgia is one of the consequences of shingles, which is in turn the consequence of the common chickenpox. Chickenpox is caused by the varicella zoster virus. Varicella zoster is very common, and most individuals are exposed to it on a regular basis; most individuals become immune to it quickly, some even before they have developed a case of the chickenpox to speak of. Others simply suffer from chickenpox and come through stronger for it. However, varicella zoster will on some occasions go dormant in the spinal fluid. After a period of time, it may resurface. This resurfacing can occur for a number of reasons, but it has a tendency to occur most commonly in individuals that are immunocompromised and unable to fight against viral infections as effectively.

When the varicella zoster virus recurs, it causes a severe ailment known as shingles. Shingles is very painful, and advanced cases of shingles that are left unchecked can be damaging to one’s productivity and day-to-day life. Shingles is nothing to play around with. However, while shingles is bad enough for the transient symptoms that it carries with it, shingles carries the very real and very strong risk of causing permanent damage.

If shingles should spread to the optic nerves, it may cause damage to the eyesight that is irreversible. This is relatively rare. What is more common is the condition known as postherpetic neuralgia.

As a neuralgia, it is marked by a pain that is not induced by nerve stimulation. That is to say, while most forms of pain stem from trauma to the skin in the form of a blister or cut, or from other uncomfortable factors, neuralgias simply hurt with no external stimulation needed. Postherpetic neuralgia tends to afflict the area that shingles afflicted, and will usually appear as shingles heals away.

Who gets Postherpetic Neuralgia?

Postherpetic neuralgia is an ailment secondary to the infection of the herpes zoster virus better known as shingles. Thus, only individuals who have suffered from shingles are at any risk to go on to suffer from postherpetic neuralgia; postherpetic neuralgia is both an ailment unto itself and a side effect of shingles.

Postherpetic neuralgia consequently is most likely to afflict the same individuals that shingles is most likely to have afflicted previously: the immunocompromised. As individuals age, they grow increasingly more likely to suffer from shingles if they previously suffered from an infection of the varicella zoster virus. This is for two reasons: the more they age, the longer they have had to be infected, and the older they are, the weaker their immune systems are likely to become.

Other factors that may weaken the immune system include various immune-system crippling diseases, like HIV. Other possibilities include steroid use, as steroids have a tendency to suppress the function of the immune system. Unfortunately enough, steroids are frequently used as a form of treatment in individuals suffering from autoimmune conditions; many individuals will be left more susceptible to shingles and therefore postherpetic neuralgia because they are receiving treatment to prevent their own bodies from causing them harm.

In addition to the increased likelihood of suffering from shingles and thus enabling them to suffer from postherpetic neuralgia, the elderly are also more likely to suffer from postherpetic neuralgia following a case of shingles. Individuals over the age of 60 are significantly more likely to suffer from postherpetic neuralgia than individuals under the age of 60—a mere 10% of individuals under 60 suffer from postherpetic neuralgia following a case of shingles, which contrasts heavily with the 40% over the age of 60 that do develop postherpetic neuralgia.

While age plays a major role statistically, the underlying cause seems to be nothing more than the suppression and weakening of the immune system, which is simply more common in individuals over 60. Young adults tend to have stronger immune systems than elderly adults. However, younger adults who are immunocompromised for any reason will be more likely to suffer from postherpetic neuralgia as well.

All in all, about a fifth of the individuals who suffer from shingles every year (about one million, in the United States alone) will go on to suffer from postherpetic neuralgia, making it a reasonably common condition.

While its role related to postherpetic neuralgia specifically is not fully understood, neuralgic pain has been shown to have a genetic link, as some genes are expressed differently in individuals who are more likely to suffer from neuralgic pain. In addition to this genetic factor, it has been found that African Americans are a mere quarter as likely to suffer from postherpetic neuralgia as Caucasians.

What causes Postherpetic Neuralgia?

The cause of postherpetic neuralgia is thought to be shingles, or more specifically the herpes zoster virus that causes shingles. Postherpetic neuralgia manifests in the same sections of the skin that shingles outbreaks do, generally presenting itself when the blistering of the skin caused by shingles has begun to scab and crust over.

The damage to the skin is inflicted on the nerves directly. A difference in genetic expression causes the virus to damage the skin in otherwise unusual ways, allowing for what could be thought of as crossed wires. As a neuralgia, postherpetic neuralgia can cause pain without actually stimulating the nerves—the nerves are simply left under the illusion that they are being damaged and stimulated.

What does Postherpetic Neuralgia cause?

Postherpetic neuralgia causes extreme and excruciating pain. Postherpetic neuralgia is not defined as ‘chronic’, per-se. However, it cannot be cured, either, merely treated until it fades away on its own. Postherpetic neuralgia does not manifest as a rash and is effectively invisible to the eye. However, it is more likely to occur in areas where the herpes zoster virus’ effects have left scarring: this is not a symptom of postherpetic neuralgia, but rather a sign that it may be present.

Other than the extreme pain that it can cause, postherpetic neuralgia is imperceptible to the senses. This has led to quite a lot of psychological damage over the years for many individuals who have suffered from postherpetic neuralgia; because it is not directly visible, many fear that they will be thought of as simply making it up–when in reality their pain is very severe and very real.

What does Postherpetic Neuralgia treatment look like?

Treatment for postherpetic neuralgia is focused, first and foremost, around prevention. Postherpetic neuralgia is one of the most severe results of shingles, and is a large part of why shingles can be as destructive as it is. Thus, much attention is given to keeping postherpetic neuralgia from ever gaining a foothold.

There is an unfortunate caveat that applies to shingles and, by extension, postherpetic neuralgia that is not a problem with many viral illnesses. Specifically, the issue is that of vaccination. Vaccinations are a solution for a great many viruses. In fact, there is an effective vaccination on the market for the varicella zoster virus that causes chickenpox and leaves individuals susceptible to shingles later in life. This vaccination is not a part of the standard regimen required in school children, but it does work—it is largely kept out of circulation because individuals are already exposed to varicella zoster so commonly.

However, vaccination does not actually insulate against shingles in any way. Individuals that have been vaccinated against the varicella zoster virus may yet go on to suffer from shingles. Shingles has a powerful tendency to occur only in the circumstance of a weakened immune system; this means that while it is possible to develop an immunity to the varicella zoster virus, the defenses will be useless against a case of shingles, which will only occur when said defenses are down. In short, how well-equipped one’s immune system is does not actually provide any defense against shingles.

This means that preventing postherpetic neuralgia cannot be as simple as preventing the virus. Postherpetic neuralgia cannot be actively avoided until shingles actually takes hold.

Once the herpes zoster virus does infect an individual, it is not uncommon for rapid and aggressive antiviral treatment to be applied. This treatment hits herpes zoster hard and fast. While it will not assuage the symptoms of shingles directly, it will prevent the herpes zoster virus from doing as much damage as it otherwise could, and will force the disease to run its course on a much smaller timetable.

Cases of postherpetic nerualgia that occur after a powerfully-treated case of shingles have a powerful tendency to be much less severe and much shorter. The severity of postherpetic neuralgia stems primarily from its length: while it is not technically chronic, it frequently persists until the death of the patient in severe cases. Thus, guaranteeing that the case cannot be severe to begin with is one of the best options on the table for anyone suffering from the herpes zoster virus.

There are other options available when a case of postherpetic neuralgia has already occurred, however.

The first item of mention is analgesics. Analgesics are a broad range of drugs also known as painkillers, and they include any individual drug that may help to suppress pain. Because postherpetic neuralgia is a neuralgia, there is no way to remove the offending substance or wound that is causing pain—there is only the option to attack the pain directly, as the pain is caused by erroneous nerve signals.

Topical analgesics are the first choice. These have a strong tendency to deliver the appropriate dosages of analgesic directly to the affected areas, allowing the nerves to cease their panic and erroneous signals, ideally resulting in a decrease in pain. The most common topical analgesics for this purpose are aspirin and lidocain; the first can be found in liquid form, and the latter is marketed in patches.

In addition to the option of topical treatments, there are also systemic treatments, which affect the whole system at once and are taken orally. These have a tendency to be stronger than the topical solutions, but may be appropriate for more widespread or stronger cases of postherpetic neuralgia. Peracetamol, marketed primarily under the brand name ‘tylenol’, is usually the first on the list of options for this purpose. In addition to paracetamol, there is help to be found in NSAID pain relievers, better known as anti-inflammatories.

Truly severe cases may warrant much stronger treatment options, including opioids. Opioids are much more powerful than any of the previously mentioned topical or systemic treatment. However, they are frequently habit-forming, and addictive. Some weak forms of codeine are available over the counter in some regions, but for the most part, these are only avaiable by prescription. Some areas of the United States have very strict regulations regarding opioids, so this may not be the most attractive option for sheer reasons of logistics. Even so, opioids frequently carry tranquilizing properties. These are very useful for resisting pain.

In addition to suppression of pain through NSAIDs, paraceteamol and opioids, there is the option of pain modification. Pain modification does not directly reduce pain, nor does it change pain into something else. What pain modification therapy does is help the brain interpret pain differently, making it much easier to cope with.

The primary options for pain modification therapy are various forms of anti-depressants. Most all anti-depressants affect major centers of chemical activity in the brain and act on serotonin and norepinephrine. Both of these are exceedingly important chemicals—without the first, it is effectively impossible to feel happiness or function, and without the latter, the heart cannot effectively beat. Antidepressants can help keep these chemicals at appropriate levels in the brain. In individuals with depression, these chemicals have a tendency to be severely out of balance. Seeing that serotonin is slightly raised can aid individuals suffering from extreme pain.

The dosages involved with pain modification therapy are traditionally much lower than those used for depression and major depression. However, dosages do vary widely from person to person, as do the appropriate anti-depressants; even when anti-depressants are being used for depression, the reason so many of them are out on the market at one time is because they are simply too complex to reduce to a single formulation. Many individuals will only respond favorably to one particular anti-depressant, and trial-and-error is roughly the only means to determine this. While this is primarily true with depression, it does extend to the use of pain modification therapy as well.

Many drugs intended to help seizure patients are effective for the reduction of pain from postherpetic neuralgia. Anticonvulsants are the primary breed of drug under this banner, and they serve to regulate muscle activity and aid with pain by keeping the nerves, for lack of a better analogy, ‘calmer’. They help to regulate and reduce abnormal electrical activity in damaged nerves, which can in turn greatly reduce the incidence of the pain signals from the nerves that result in postherpetic neuralgia.

There are a number of treatment options available that do not involve chemical intervention. Many of these tie in to pain management rather than reduction, and revolve around equipping an individual to tolerate pain, rather than actually reducing their pain to a level they can cope with.

Relaxation therapy is high on this list. Relaxation therapy focuses around breathing exercises which are specifically tailored to calm, and frequently use forms of imagery or auditory therapy to keep individuals at peace. This can help them distract themselves from the pain at hand and allow them to function normally while the pain gradually subsides over time.

Thermal forms of therapy are frequently employed. Both heat and cold can be used to stimulate the nerves in more pleasing and distracting ways, or in any case, in ways that do not trigger the erroneous pain responses. This can make all the difference on its own. These are frequently accomplished with heating pads and cold packs.

Electrical nerve stimulation is an option for some cases of postherpetic neuralgia. Specifically called Transcutaneous Electrical Nerve Stimulation, it revolves around putting low electrical signals through the skin, and by extension the nerves. This stimulation of the nerves results in a decrease in pain and helps to normalize abnormal nerve signal activity, greatly reducing the pain caused by erroneous nerve signals.

Corticosteroids are prescribed in a number of cases to aid with postherpetic neuralgia. While corticosteroids have a great number of uses elsewhere in medicine, recent studies have indicated that there is little to no benefit in their use in postherpetic neuralgia treatment.

Treatment for postherpetic neuralgia is focused around pain reduction and pain management. Neuralgias have a great tendency to be severe, and postherpetic neuralgia is unfortunately no exception to this. The pain of postherpetic neuralgia is so severe that many individuals lose the ability to function normally, frequently needing to call in sick. Many others without the option of sufficient sick days or employment allowances may lose their jobs. Treatment is critical to reduce pain to the greatest degree possible.

Some individuals can be completely put out of pain by postherpetic neuralgia treatment. This is generally truest in the less severe cases of postherpetic neuralgia that do not require such powerful treatments; severe and persistent cases of postherpetic neuralgia that require opioid drugs may only be somewhat reduced. Many individuals find that treatment does not reduce their pain to any degree.

How do I know if I have Postherpetic Neuralgia?

Postherpetic neuralgia is something that should not be self-diagnosed under any circumstances; simply put, anyone suffering from shingles should be in contact with a medical professional as soon as possible to receive whatever treatment is available to them. Early, rapid and aggressive shingles treatment is the best option available to deal with postherpetic neuralgia, as it can pre-emptively reduce the severity of a case of postherpetic neuralgia and afford an individual a much greater chance of the pain simply resolving itself—which is ultimately the only safe conclusion to be hoped for, as it cannot be cured.

Even so, there are several indicators for postherpetic neuralgia. The first is the outbreak of herpes zoster, better known as an outbreak of shingles. If an outbreak of shingles has not occurred, then a case of postherpetic neuralgia is not on the table as a possibility for anyone.

Shingles results in a blistering rash. As this rash progresses, it has a tendency to secrete fluids, crust over and scab. This is frequently when postherpetic neuralgia is most likely to begin developing. If this crusting rash should leave behind a scar, postherpetic neuralgia may be more likely.

Postherpetic neuralgia is characterized by lasting pain in the areas of skin that were initially affected by the herpes zoster outbreak. ‘Lasting pain’, in this case, is thought of as being in excess of three months. Prior to that it may simply be the case of shingles still resolving from the system. If shingles has left the system entirely and the pain persists, than a case of postherpetic neuralgia is more likely.

It is not common for any form of lab work to be required. Any medical professional providing treatment for shingles will be aware of postherpetic neuralgia and the likelihood of its resulting from a case of shingles. Anyone in touch with a medical professional and receiving treatment for shingles will thus have someone watching them progress through the stages of the ailment, and postherpetic neuralgia can be easily identified on symptoms alone. However, there is the option of taking spinal fluid for a postive diagnosis; over 60% of individuals suffering from postherpetic neuralgia will show abnormalities in their spinal fluids.

MRI scans of individuals suffering from herpes zoster have indicated that postherpetic neuralgia may be visible on brain scan. Lesions may display themselves that can be attributed to herpes zoster; roughly half of all individuals suffering from herpes zoster displayed these lesions. Half of the individuals displaying lesions then went on to develop postherpetic neuralgia. Thus, there is some validity to using imaging to predict postherpetic neuralgia.

However, these advanced diagnostic methods are rarely, if ever required: postherpetic neuralgia can be easily identified by its symptoms and the pre-existance of shingles.

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