Post-zoster neuralgia is a complication of shingles. It is thought to be the result of permanent damage to the nerve caused by the varicella-zoster virus.
What is post-zoster neuralgia?
Post-zoster neuralgia (PZN) occurs in 10 to 15 percent of all patients with shingles (herpes zoster). Affected individuals suffer neuropathic pain in the area of the previous zoster infection. PZN is significantly more common in facial herpes zoster than in other zoster localizations. The likelihood of experiencing post-zoster neuralgia after shingles also increases with age. The pain is sometimes very severe. Pain medications also do little or nothing to help. A cure for post-zoster neuralgia is not possible; the pain persists. Because of the persistent severe pain, patients with PZN are often suicidal.
Causes
The cause of post-zoster neuralgia is infection with the varicella-zoster virus. Such an infection is colloquially called shingles. Varicella-zoster virus belongs to the herpes virus family. It is closely related to the herpes simplex virus. According to estimates, the contamination with the virus is high. Around 90 percent of all Europeans over the age of 14 are carriers of varicella zoster virus. The pathogens rarely cause diseases with a fatal course. This shows how strongly the viruses have adapted to their reservoir host, humans. The initial infection with the virus usually manifests itself as chickenpox. The pathogens are transmitted by droplet infection. Smear infections are also possible. After the chickenpox disease has subsided, the infected person is immune to chickenpox for life. However, the varicella zoster virus remains in the body. Due to a suppressed immune system, the virus can be reactivated at any time later. Common triggering factors are stress or strong sun exposure. The viruses persist in the nerve roots of the spinal cord, in the so-called spinal ganglia, and in the ganglia of the cranial nerves. When the virus reactivates, shingles rather than chickenpox occurs again. Post-zoster neuralgia results from disturbed transmission of stimuli caused by the viruses on the nerves. In the process, the viruses can leave permanent damage on the affected nerves. These cause the chronic pain.
Symptoms, complaints, and signs
Post-zoster neuralgia is always the result of shingles. The viral disease appears as a painful rash with blisters on one side of the body. In this case, the rash runs in stripes on a specific dermatome. A dermatome is an area of skin that is innervated by a spinal nerve. In most cases, shingles is preceded by a so-called prodromal stage. In this early stage, symptoms include fatigue, fever and tiredness. Burning, pain and discomfort may also occur in the affected dermatome. The typical rash does not form until several days later. The nerve tissue is inflamed and the affected person suffers from burning and severe pain in the dermatome supplied by the inflamed nerve. The nerve cord itself may also hurt. Within a few days, the resulting blisters fill and break open. Healing can take two to four weeks. Usually, the pain also resolves within a few weeks. However, neurological pain can continue for a very long time due to permanent nerve damage. This is called post-zoster neuralgia. The pain can appear in different forms. It can be permanently burning and drilling or occur in the form of short and violent pain attacks. Severe touch pain is also typical of post-zoster neuralgia.
Diagnosis and course of the disease
Diagnosis is made on the basis of the presenting symptoms, medical history, and physical examination. If post-zoster neuralgia occurs in younger patients, the reasons for immunodeficiency should always be sought. In young patients, post-zoster neuralgia occurs only in very rare cases without an immunosuppressive cause. The immune system disorders may be acquired or congenital. Malignant diseases such as tumor diseases and leukemias must be clarified in any case.Systemic diseases and infectious diseases such as AIDS should also be excluded.
Complications
Depending on the intensity and duration of postherpetic pain, depressive moods, the development of clinically manifest depression, easy fatigability and lassitude may occur. Also, difficulty falling asleep and staying asleep, – decreased appetite and also difficulty concentrating. The highest risk for these complications are individuals who have neuropathic pain for more than one year. High pain intensity also increases the likelihood of late complications. Because treatment for post-zoster neuralgia is symptomatic according to pain quality, complications can also result from inadequate or improperly administered pain therapy. This is particularly true of antidepressants containing the active ingredients nortriptyline, duloxetine, and venlafaxine, which are used both to treat depression and in pain therapy. Dosages commonly chosen for the treatment of neuralgia are often inadequate for depression treatment and may need to be adjusted. Anticonvulsants containing the active ingredients gabapentin and pregabalin, which are also used to reduce post-herpetic pain, can exacerbate pre-existing complications such as fatigue and poor concentration. This applies to an even greater extent to painkillers from the opioid class of active ingredients (tramadol, oxycodone, morphine). Their partially desired sedative effect can interact with existing complications and other analgesics to cause severe fatigue, drowsiness and confusion. Therefore, regular adjustment of pain therapy should be made to prevent complications.
When should you see a doctor?
If severe nerve pain suddenly occurs, a visit to the doctor is recommended. Post-zoster neuralgia can be treated well, provided it is detected early. Therefore, even initial nerve discomfort, problems moving the limbs, and other unusual phenomena should be investigated and treated by a doctor if necessary. Anyone who has recently contracted the varicella-zoster virus should consult their family doctor. It is possible that the neuralgia was triggered by the pathogen. People with a weakened immune system, nerve diseases and a pronounced shingles should also consult the doctor if the described symptoms occur. Medical advice is required at the latest when the symptoms have a very negative effect on the well-being or lead to further physical or mental complaints. In addition to the general practitioner, post-zoster neuralgia can be taken to a neurologist or internist. Chronic conditions may require inpatient treatment at a specialized clinic. Sufferers should discuss with the doctor which measures promise the best prospects of recovery with regard to the symptom picture and any previous illnesses.
Treatment and therapy
Post-zoster neuralgia can be cured only in very rare cases. If the disease began less than six weeks ago, sympathetic blockade can be performed. Intravenous regional sympathetic blockade involves injecting a medication into a vein that is right next to the affected area of skin. The sympathetic drug administered can relieve pain. If the condition persists for more than six weeks, this method is not promising. Affected patients are given painkillers such as tramadol or pregabalin. Antidepressants or gabapentin are also administered in low doses. They can inhibit pain transmission in the brain and at the same time relieve depressive moods. Many patients with post-zoster neuralgia suffer from depression due to the severe pain. Psychotherapy may also be used to help patients cope with their condition. In some cases, local anesthetic ointments or patches are used. Some doctors also treat post-zoster neuralgia with capsaicin cream. Capsaicin, an active ingredient in chili pepper, binds to pain receptors in the skin and interferes with the transmission of stimuli. Accompanying pain medication, transcutaneous electrical nerve stimulation (TENS) can be performed. In this procedure, the patient wears a small device that is connected to the affected skin area via an electrode. When pain occurs, the patient can deliver electrical impulses.These irritate the skin nerves and impede the transmission of pain impulses.
Prevention
To prevent post-zoster neuralgia, any shingles should be treated early with antiviral medications such as valaciclovir and aciclovir.
Follow-up
After the actual herpes infection has cleared, some patients may experience discomfort or even pain in the affected area. Treatment of these symptoms requires the active assistance of the patient, otherwise the symptoms may become chronic. First of all, it is important to take the correct medication prescribed by the doctor. In addition, pain-relieving gels help. Acupuncture and TENS therapy have also shown success in treatment. TENS therapy is a gentle variant of electrotherapy. A stimulation device generates stimulation current that blocks the excitation conduction of the nerve fibers so that they cannot transmit the pain impulse to the brain. TENS units are also available for home use, which greatly simplifies their use. Appropriate relaxation techniques, such as Jacobson’s Progressive Muscle Relaxation, can also help against the discomfort and pain. Yoga, Reiki or certain breathing exercises also enable patients to relieve the discomfort of post-zoster neuralgia and deal with it more calmly. In particularly severe cases or if the pain has already become chronic, psychotherapeutic therapy can be used in addition to drug treatment to help the patient lead an independent and carefree life as far as possible.
What you can do yourself
These sensations of discomfort or pain that occur after a herpes infection are particularly annoying for patients because the actual infection has already subsided. Nevertheless, they should actively participate in the treatment, otherwise the discomfort could become chronic. Treatment includes taking the correct medication prescribed by the doctor. In addition, pain-relieving gels can be used. Furthermore, IGEL services such as acupuncture and TENS therapy have proven their worth. In TENS therapy, electrodes are attached to the painful areas, through which a stimulation current of 80 to 120 hertz is then passed. The tingling sensation on the skin that results from this overlays the pain on the one hand and causes the body to release endorphins on the other. These endorphins dock onto the pain receptors. In this way, the stimulation current therapy can switch off pain. TENS units are also available for home use, which simplifies their use. Relaxation techniques can also help against the pain and discomfort. For this purpose, for example, the effective and easy-to-learn progressive muscle relaxation according to Jacobson is recommended. Meditations, breathing exercises, Reiki, yoga and EFT tapping acupressure are also good ways of counteracting the pain and dealing more calmly with post-zoster neuralgia. If the pain is particularly severe or has already become chronic, accompanying psychotherapeutic treatment is recommended in addition to drug therapy.
