The life long burden of suffering from postherpetic neuralgia is reduced by adult vaccination and by topical anti-hyperalgesic treatment with lidocaine and capsaicin

In this issue of the Scandinavian Journal of Pain Ewa Gawecka and Oddbjørn Viken review recent development in prevention and treatment of acute herpes zoster (shingles) and postherpetic neuralgia [1]. They review advances in symptom management in those unfortunate elderly patients who do develop acute herpes zoster and end up with a protracted and difficult to treat, often life long postherpetic neuropathic pain condition [1].

Reactivation of the dormant varicella-zoster virus (VZV) after childhood chickenpox (varicella) in the dorsal ganglia causes acute herpes zoster (HZ) in about 1 per 100 elderly persons each year [1,2,3]. Postherpetic neuralgia (PHN) follows HZ in about 20% [3]. Postherpetic neuralgia is a major cause for lost quality of life in elderly persons because of this peripheral and central neuropathic pain condition that has been so difficult to treat [3].

There is usually a constant burning, aching type of pain in the affected dermatome(s), but the most distressing is dynamic mechanical allodynia: lightly touching the skin, clothes rubbing or moving softly against the skin will provoke attacks of severe, shooting pain.

Vaccination against varicella is now part of childhood vaccination programs in some countries. We will not know for another 4–5 decades whether HZ will be less or more frequent in countries with a VZV-vaccination program: It is possible that vaccination improves immunity against the VZV for longer and therefore the risk of reactivation of the varicella virus will be reduced. However, it may be that an episode of varicella in childhood will cause a more robust immunity than the vaccination. Whether vaccinated in childhood or not, immunity slowly diminishes with age, so that the balance between the immune defence and the dormant VZV in the ganglia of spinal and cranial sensory nerves tips in favour of the VZV.

Therefore, it is highly important, that the long awaited adult VZV-vaccination now is firmly documented to reduce incidence of HZ by more than 50% and PHN by more than 66% [3,4].

Systemic drugs can reduce suffering from PHN [3], but they all have side effects that are problematic in the elderly patients [3]. The risk of dizziness, sedation, and falling increases with TCA and other antidepressive drugs. Similar problematic side effects occur with the antiepileptic drugs that have anti-hyperalgesic effects [3].

Therefore, topical treatments may be safer than systemic drugs in elderly patients with PHN. Locally applied lidocaine cream or patch relieves many of the hyperphenomena, such as touch provoked mechanical allodynia [3]. However, the effect from topical lidocaine is transient, disappearing soon after removal of the patch. Daily applications are necessary. Too much, when large areas are affected by PHN, and too long topical lidocaine may cause enough absorption into the systemic cirdculation to create systemic side effects. For some of the elderly, often partly disabled patients it may also be difficult to apply in some dermatomes.

Capsaicin cream (0.075%) has been available in many countries for more than 20 years, but did not become widely accepted because it must be applied 2–3 times per day for several days before any effect develops. Messy, impractical, and not very effective.

Recently an 8% capsaicin patch has been documented to reduce hyperphenomena in PHN to a significant degree, and the effect lasts for up to 3 months, at which time it can be reapplied [5,6].

Thus, lidocaine 5% patches and capsaicin 8% patches are effective topical anti-hyperalgesics with little or no systemic side effects. Local tenderness after application of the capsaicin patch may be bothersome, but it is transient.

Adult vaccination and topical treatments are costly for the patients in countries where these drugs are not reimbursed by the health insurance. However, they reduce the burden on the health related quality of life of many patients and the economic burden on the health care system. Thus, they are cost-effective for society. “The cost-effectiveness of the varicella zoster vaccine varies substantially with patient age and often exceeds $100,000 per quality-adjusted life year saved” [7]. Age should be considered in vaccine recommendations [4,7].

The elderly populations are increasing rapidly in most western countries, especially in North-Western Europe. The risk of having HZ increases with age, significantly after 60, and accelerating after 70 years of age. Therefore, health care policy makers in the Nordic countries must be made aware of the major benefits these topical drugs and adult vaccination confer to the elderly population and to the health budgets.

In Norway, the lidocaine patch and the capsaicin patch may, or may not, be reimbursed after special application to the national health insurance, for each patient.

But it is not at all acceptable that adult vaccination against VZV that does reduce the risk of HZ by more than 50% and PHN by more than 66%, has to be paid in full (about US $5–600) by elderly persons.

Therefore, only few will benefit from this effective and safe vaccine: Those who know that they have a 30% life-time risk of having HZ and the calamities that follow, can afford to pay, and are willing to pay about $ 500 to reduce that risk.

It is now important that our health care policy makers and those responsible for health budgets are made aware of these important facts: The life-long suffering from PHN can be prevented by 2/3 at a significant saving in health care budgets. Unfortunately there is a major barrier to change: health-related quality of life of the elderly population has low priority among health care policy makers.