Corticosteroids for Preventing Postherpetic Neuralgia After Herpes Zoster Infection.

Abstract

Postherpetic neuralgia (PHN) is a painful condition of persistent chronic pain following acute reactivation of varicella zoster virus. The review defines PHN as persisting or recurring pain at the site of shingles at least 1 month after the onset of the acute rash. The incidence of shingles increases with age, almost doubling in each decade after 50 years of age. Of these cases, roughly 20% go on to develop PHN, with age again being the strongest risk factor.1 The pain of PHN is frequently debilitating and can significantly affect quality of life. It is thought that the anti-inflammatory effects of corticosteroids might decrease nerve damage and prevent PHN. This Cochrane review is an update of a previous Cochrane review first published in 2008 and updated in 2010. This update concludes based on moderate-quality evidence that steroids do not provide benefit in the prevention of PHN, whereas prior reviews indicated insufficient evidence to draw a conclusion. More up-to-date data analysis methods were used in this review to provide conclusions It included all randomized controlled trials in which corticosteroids were given by oral, intramuscular, or intravenous routes within 7 days after onset of rash and in which steroids were compared to either no treatment or to placebo. Five trials with a total of 787 patients were included. The meta-analysis provides moderate-quality evidence that corticosteroids are not effective in preventing PHN 6 months after onset of acute herpetic rash (relative risk = 0.95, 95% confidence interval = 0.45 to 1.99). The review found no statistically significant difference in the secondary outcome of pain severity at 3, 6, or 12 months. Nonserious adverse events were recorded in all of the trials, and there were no statistically significant differences between steroid and placebo. Serious events, including pneumonia, myocardial infarction, cardiac insufficiency, and death, for example, were reported in three of the trials, but there were no statistically significant differences between steroid and placebo (6/376 [1.6%] and 3/379 [0.8%], respectively). Two of the trials made note of the absence of serious adverse events in the steroid groups. The Cochrane authors suggest that future trials should include measurements of function and quality of life and, furthermore, that there should be longer-term follow-up to determine an effect of steroids on the likelihood of transition from acute pain to PHN. Of the five trials included in the study, the authors of the Cochrane review were able to perform meta-analysis on only two (amounting to only 114 participants) to examine the incidence of the primary outcome. Of these two trials, one was rated as having a high risk of bias because of incomplete outcome data; the other was rated as having a low risk of bias overall. The three remaining trials were not included in the meta-analysis because outcomes were reported only at less than 1 month because of inadequate data. Two of the trials were performed at single centers, and the others, at multiple centers. Data regarding pain measurement were also lacking. The best validated pain scales, the visual analog scale or numerical descriptive scale, were not used in any of the trials. Four of the trials reported on changing pain intensity but used different methods of pain evaluation and could not be combined into the meta-analysis. Although it was not the focus of the review, two of the trials suggested that steroids might have a significant effect on reducing acute pain and in accelerating healing of acute herpes zoster in the first month. The authors suggested that further studies to assess the effect of steroids on short-term pain and PHN should be performed. Because of limited data and high risk of bias, it is difficult to draw any meaningful conclusion about the use of corticosteroids in reducing PHN after shingles. However, the existing limited evidence does not support the use of this treatment. Therefore, we assign a color rating of red (no benefit) to this treatment. Editor's Note: Brass Tacks are concise reviews of published evidence. This series is a result of collaboration between Academic Emergency Medicine and the evidence-based medicine website, www.TheNNT.com. For inquiries please contact the section editor, Shahriar Zehtabchi, MD (Shahriar.zehtabchi@downstate.edu).