Risk Factor and Prevention of Postherpetic Neuralgia

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Herpes zoster (HZ) and postherpetic neuralgia (PHN) are common diseases in a pain clinic. In Korea, the rate of clinical visits due to the incidence of herpes zoster was 7.93-12.54/1000 annually [1]. PHN is a painful neuropathy and the most common complication of HZ. A complete recovery from PHN is difficult for doctors despite of proper HZ treatment. In spite of the treatment, some patients suffered from severe PHN for several years. Therefore, the most important aspects are the risk factor of PHN and the method of prevention of PHN. In this issue of the Korean Journal of Pain (KJP), Jung et al. [2] reported the incidence of HZ in Cheonan, Korea. The results show that patients 50 years and older have a higher incidence of HZ, and the most common site of HZ was the thoracic nerve (47.9%), followed by the trige-minal nerve (21.4%). The incidence rate was similar to the affected site of PHN (thoracic area: 52.9%, trigeminal area: 15.6%) in Korea [3]. In patients who suffer from HZ, the risk factors of PHN are old age, presence of a painful prodrome, severe pain of HZ, severe rash, and immuno-compromised status [4-6]. In patients with HZ over 60 years, up to 25% progressed to PHN [7]. The proportion of PHN increases steadily from young ages up to 80-84 years [8]. Therefore, patients who are elderly and possess the risk factor with HZ must undergo more intensive treatment. The main treatment of HZ is medication and inter-ventional therapy. Taking antiviral medication beginning within 72 hrs of rash onset is usually recommended [7,9,10]. Two meta-analyses suggest that the antiviral medication can reduce the overall duration of pain and incidence of PHN [11,12]. Epidural injection with a steroid within 2 months of HZ development is also recommended for the prevention of PHN [13]. In the previous survey of Korea, epidural injection was the most commonly performed interventional treatment in PHN patients [3]. Other interventions such as paraverte-bral block, peripheral block and sympathetic block are clinically effective for the treatment of HZ and PHN. For evidence-based medicine of interventional treatment of HZ and PHN, the investigations of randomized controlled trials regarding the interventions will be necessary. …