Postherpetic Neuralgia: Symptoms and Treatment

Postherpetic neuralgia is the most common complication of herpes zoster. Disease, although not dangerous to human life, but very painful. Postherpetic neuralgia does not allow a person to sleep, work, causes depression and dramatically reduces the quality of life. Theoretically, it can occur after any episode of shingles, although there are some predisposing factors. Duration of the disease is different: on average it is about 12 months, but in some cases this pathology can persist for years. Various groups of drugs are used to treat the disease. At present, preference is given to anticonvulsants. In this article, we will talk about the causes of postherpetic neuralgia, symptoms and methods of treatment.

Postherpetic neuralgia refers to a whole class of pain sensations: neuropathic pain, which has its own characteristics. So, among all the existing types of neuropathic pain, postherpetic neuralgia ranks third in prevalence, yielding the palm of primacy only to the pains in the lower back and diabetic pains.

Herpes zoster - what is it?

Herpes zoster (herpes) is the result of the reactivation of the herpesvirus type 3 (Varicella zoster). Reactivation, because the first encounter with this virus ends for a person with the development of chicken pox. After chickenpox, the virus is hiding in the nerve ganglia for life. With a decrease in immunity, he emerges from the "shelter", multiplies and causes damage to nerve conductors and skin, which is called shingles.

Herpes zoster lasts about 3-4 weeks. The disease is characterized by the appearance on the skin of the bubbles, which then dry up and form crusts. When the crust disappears, the pigmentation remains for some time. Eruptions are located in the affected nerve ganglion: in the form of transverse bands on the trunk, longitudinal bands on the limbs and in the zone of innervation of the cranial nerves on the face and head. In this case, the appearance of the rash and all stages of its development are accompanied by itching, burning, pain of varying intensity and nature (shooting, drilling, blunt and aching, burning and so on), as well as temperature increase and intoxication. With a favorable outcome, shingles pass without a trace. In some cases, he leaves after himself a postherpetic neuralgia. When does it arise and why? Let's find out.

Causes of postherpetic neuralgia

In medicine, it is considered that postherpetic neuralgia arises as a result of the inflammatory process in the nervous ganglia and peripheral nerves. Inflammation provokes a multiplying virus. Violated interaction and a reasonable balance between pain and analgesic systems in the body, the mechanism of control over the excitability of painful neurons to the central nervous system suffers.

However, neuralgia complicates not all cases of shingles. The risk factors for its development are:

• elderly age. According to statistics, the incidence of postherpetic neuralgia in people over 60 years is 50%, that is, every second case ends painfully for the patient. While in the age group from 30 to 50 years this complication occurs with a frequency of 10%. After 75 years, the disease affects 75% of patients. The figures speak for themselves. Presumably, the main role in this is played by the ability to regenerate (i.e., healing), the rapid elimination of the inflammatory process in young people and the decrease in immunity in old age;
• location of the rash. Postherpetic neuralgia develops more often when the rash is localized on the trunk;
• Massiveness of rashes. The larger the lesion area, the more likely the development of neuralgia. Indirectly, this may be due to a low immune response, an inability of the organism to localize the lesion with one or two ganglia;
• the severity of the pain syndrome in the acute period (in the period of the appearance of the rash). The stronger the pain in this period, the higher the probability of postherpetic neuralgia;
• the time to start taking antiherpetic drugs that block the multiplication of the virus. The later a specific treatment is initiated, the higher the likelihood of complications.

Separately from this list it is worth noting the more frequent occurrence of postherpetic neuralgia in female subjects, which so far has no explanation.

Symptoms of postherpetic neuralgia

With herpes zoster after the disappearance of the rash, pain can remain for several more weeks.

Under postherpetic neuralgia, it is common to understand pain that persists after healing of the rashes. Pain can be felt by patients from 3-4 weeks to several years. On average, this kind of neuropathic pain exists for about a year.

What character is the pain? It can be of several types:

• constant. The pain usually has a blunt, pressing, deep character with a burning sensation;
• periodic. This kind of pain manifests itself as a shooting, stabbing, acting like "electric shock";
• allodic. This pain is a sudden, burning nature that arises in response to a slight touch, like an inadequate response to an external stimulus. For example, touching clothes can cause such feelings.

One patient may have all three types of pain at the same time.

The pain spreads along the course of the affected nerve wires, that is, it is felt where the rash was localized, although there are no manifestations on the skin.

In addition to pain, other sensory sensations may appear in the affected area, which, nevertheless, also cause unpleasant sensations. It can be:

• itching;
• numbness;
• tingling, a feeling of crawling, of the presence of a foreign body ("some insect sits", "something stuck" and so on).

Usually the affected area has an increased sensitivity to any touch (although it can feel numbness of the skin itself).

Although the main manifestation of the disease is only pain, it causes changes in other areas of human life, harming it. Painful sensations provoke:

• decreased physical activity;
• insomnia;
• chronic fatigue;
• decreased appetite and, in this regard, even body weight;
• a state of anxiety and constant anxiety, which in some cases results in depression;
• decrease in social activity.

As we see, postherpetic neuralgia leads to a decrease in the quality of life of a sick person. Therefore, it is necessary to actively combat it. To do this, resort to medication.

Treatment of postherpetic neuralgia

In order to reduce the risk of postherpetic neuralgia, it is necessary to begin treatment of the shingles depriving anti-herpetic drugs (from the Acyclovir group) within the first 72 hours from the onset of the disease. In this way, the active multiplication (and hence spread) of the virus is blocked and the area of ​​rashes is reduced. Consequently, the risk factors for postherpetic neuralgia, which can be influenced, are eliminated.

To date, the following tools are used to combat postherpetic neuralgia:

• anticonvulsants;
• tricyclic antidepressants;
• patches with lidocaine;
• capsaicin;
• opioid analgesics.

Conventional analgesics and non-steroidal anti-inflammatory drugs (Ibuprofen, Diclofenac, Nimesulide and others) are ineffective in fighting neuropathic pain.

Anticonvulsants

Of this group of drugs used Gabapentin (Gabagamma, Tebantin, Neurontin, Convalis, Catena) and Pregabalin (Lyrics, Algerika). A feature of the use of gabapentin is the need to titrate the dose to an effective dose. It looks like this: on the first day of intake, the dose is 300 mg 1 time in the evening; in the second - 300 mg in the morning and in the evening; in the third - 300 mg 3 times a day; fourth, the fifth, sixth day - in the morning of 300 mg, in the afternoon of 300 mg, in the evening of 600 mg; the seventh, the eighth, the ninth, the tenth day - in the morning of 300 mg, in the afternoon of 600 mg, in the evening of 600 mg and so on on the increasing. Usually the effective dose is 1800-3600 mg / day. When the pain stops, a person should take a maintenance dose of about 600-1200 mg / day. Pregabalin is prescribed in a dose of 150-300 mg / day, dividing the dose into 2-3 doses. These drugs are very well tolerated, rarely cause side effects (dizziness, drowsiness), which is important for older people who have comorbidities. The disadvantage is their relatively high cost.

Tricyclic antidepressants

From this group it is customary to use Amitriptyline and Nortriptyline. And in elderly people it is preferable to use Nortriptyline because of its better tolerability. They are shown to patients with concomitant mental disorders (depression). The dose of Amitriptyline is from 12.5 to 150 mg / day, Nortriptyline - from 25 to 100 mg / day. It should be borne in mind that these drugs are contraindicated in case of myocardial infarction, prostatic hypertrophy, glaucoma. Therefore, their appointment requires a careful study of the patient's medical history and the state of health in general.

Plasters with lidocaine

Such patches have become quite popular recently due to ease of use and exclusively local application. The plaster (Versatis) is glued to the affected area and left for 9-12 hours. The maximum number of patches that can be used within a day is three. In addition to direct analgesic action, the patch protects the skin from external influences (touching, rubbing clothes), which in itself reduces pain. The advantage of plasters is the lack of systemic effects, since lidocaine is absorbed locally, with virtually no effect on other organs and tissues.

Capsaicin

Capsaicin is a substance derived from red hot pepper. Used in the form of ointment (capsaicin ointment, Nikoflex and others). Suitable is not all, because the very application of the ointment can be accompanied by a significant burning. The mechanism of action of the drug is based on the exhaustion of pain impulses, that is, the phase of anesthesia does not come immediately. Ointment should be applied 3-5 times a day.

Opioid analgesics

This group of drugs should be used, if possible, in a limited way. Basically, this line of funds is prescribed for intolerable pain for a short period of time and, of course, only by a doctor. It is possible to combine them with Gabapentin or Pregabalin. Most often of this group of drugs used Oxycodone, Tramadol, Morphine, Methadone.

Another means, but already non-pharmacological aid for postherpetic neuralgia is acupuncture. In a number of cases, she can independently help in getting rid of painful pains.

There are also folk methods of treating postherpetic neuralgia. The most common of these are:

• fritters from black radish juice;
• rubbing from garlic oil (for example, 1 tbsp. l. oil diluted in 500 ml of vodka, rub 2-3 times a day);
• herbal compresses (leaves wormwood, geranium);
• ointments based on propolis and beeswax.

It should be noted that for the treatment of postherpetic neuralgia, it is often necessary to combine different methods, since when used separately they give insufficient effect.

Postherpetic neuralgia refers to those diseases that are easier to prevent than treat. Of course, this is not always possible, but the timely treatment of herpes zoster in most cases helps to avoid this painful complication. It should also be remembered that postherpetic neuralgia often ends in recovery and very rarely persists for many years, so if you experience symptoms of postherpetic neuralgia, you should not despair. Time and competent treatment will do their job, and the disease will recede.