Post-herpetic neuralgia

Abstract

BackgroundIn spite of the large body of evidence available in the literature, definition and treatment of Post-Herpetic Neuralgia (PHN) are still lacking a consistent and universally recognized standardization. Furthermore, many issues concerning diagnosis, prediction and prevention of PHN need to be clarified in view of recent contributions.ObjectivesTo assess whether PHN may be better defined, predicted, treated and prevented in light of recent data, and whether available alternative or adjunctive therapies may improve pain relief in treatment recalcitrant PHN.MethodsSystematic reviews, meta-analyses, randomized controlled trials, cohort studies and protocols were searched; the search sources included PubMed, Cochrane Library, NICE, and DARE. More than 130 papers were selected and evaluated.ResultsDiagnosis of PHN is essentially clinical, but it can be improved by resorting to the many tools available, including some practical and accessible questionnaires. Prediction of PHN can be now much more accurate, taking into consideration a few well validated clinical and anamnestic variables. Treatment of PHN is presently based on a well characterized array of drugs and drug associations, including, among others, tricyclic antidepressants, gabapentinoids, opioids and many topical formulations. It is still unsatisfactory, however, in a substantial proportion of patients, especially those with many comorbidities and intense pain at herpes zoster (HZ) presentation, so that this frequent complication of HZ still strongly impacts on the quality of life of affected patients.ConclusionFurther efforts are needed to improve the management of PHN. Potentially relevant interventions may include early antiviral therapy of acute HZ, prevention of HZ by adult vaccination, as well as new therapeutic approaches for patients experiencing PHN.

Postherpetic neuralgia: epidemiology, pathophysiology, and pain management pharmacology

“…2 , 11 When damaged, peripheral and central nerve fibers may develop a lower threshold for action potentials, discharge spontaneously, and exhibit disproportionate responses to stimuli, resulting in peripheral sensitization and pain without painful stimuli (allodynia). 2 , 11 Patients with PHN experience three major types of pain: 1) constant pain without a stimulus (often described as burning, aching, or throbbing), 2) intermittent pain without a stimulus (often described as stabbing, shooting, or electric shock-like), and 3) pain brought on by a stimulus but is disproportionate to the stimulus (hyperalgesia), 2 , 3 enduring for at least 3 months after healing of the HZ-related skin rash. In addition, patients may experience a variety of abnormal sensations (dysesthesias or paresthesias).…”

“…The safety and tolerability of pharmacologic therapies are important issues to consider as PHN affects primarily an older population. 2 , 3 , 12 Once PHN has been diagnosed, treatment should be directed at pain control and minimizing treatment-related adverse events. No single best treatment has been identified.…”

“…Postherpetic neuralgia (PHN) is a neuropathic pain syndrome characterized by pain that persists for months to years after resolution of the herpes zoster (HZ) rash. 1 – 3 HZ, also known as shingles, is a distinctive clinical condition caused by the reactivation of varicella zoster virus (VZV), which starts residing latently in the body after a primary varicella (chickenpox) infection, which may have occurred decades earlier. 1 , 2 Reactivation of VZV can also produce chronic neuropathic pain without rash (zoster sine herpete), which can be more challenging to diagnose and may involve testing the cerebrospinal fluid.…”

Pharmacological Management of Neuropathic Pain: Current Trends and Possible Approaches

“…A brief discussion of this category is provided at the end. Furthermore, reactivation of dormant varicella-zoster virus in spinal and cranial sensory ganglia, where it exists in latent state postinfection with chickenpox results in sensory root, changes, sometimes leading to complete loss of small and large diameter sensory fibers (13). These changes lead to spontaneous discharges, lowered threshold for action potential generation ultimately resulting into allodynia.…”

Relationships Among Adverse Events, Disease Characteristics, and Demographics in Treatment of Postherpetic Neuralgia With Gastroretentive Gabapentin

“…Postherpetic neuralgia (PHN) is a neuropathic pain syndrome that persists for months to years after resolution of the herpes zoster (HZ) rash (shingles). 1 HZ is an infection resulting from reactivation of the varicella-zoster virus that has been dormant for many years after the primary infection (chickenpox). 2 As many as 20% of patients with HZ develop PHN, and the risk, frequency, and severity of PHN increases with advancing age.…”