David Ronald John Griffin

Risk factors for postherpetic neuralgia in patients with herpes zoster

Objectives: To identify risk factors for postherpetic neuralgia (PHN) using a validated definition of this chronic neuropathic pain syndrome, to determine combinations of risk factors that identify patients with a high risk of developing PHN, and to examine the characteristics of patients with subacute herpetic neuralgia, that is, pain that persists beyond the acute phase of herpes zoster but that resolves before PHN can be diagnosed. Methods: The authors examined baseline and follow-up data from 965 herpes zoster patients enrolled within 72 hours of rash onset in two clinical trials of famciclovir. Results: Univariate and multivariate analyses indicated that older age, female sex, presence of a prodrome, greater rash severity, and greater acute pain severity made independent contributions to identifying which patients developed PHN. Patients with subacute herpetic neuralgia who did not develop PHN were significantly younger and had less severe acute pain than PHN patients but were significantly more likely to have severe and widespread rash than patients without persisting pain. Conclusions: The independent contributions to the prediction of PHN made by older age, female sex, presence of a prodrome, greater rash severity, and greater acute pain severity suggest that these risk factors reflect different mechanisms that each contribute to the development of PHN. Subacute herpetic neuralgia that does not progress to PHN may reflect peripheral tissue damage and inflammation caused by a particularly severe or widespread rash.

Acute pain in herpes zoster: the famciclovir database project

&NA; The results of a considerable number of recent prospective studies have demonstrated that greater acute pain severity in herpes zoster patients is associated with a significantly greater risk of developing postherpetic neuralgia (PHN). Only a few studies have examined the relationships between acute pain severity and demographic characteristics and clinical features of patients with herpes zoster, however, and the results of these studies have been inconsistent. To clarify these relationships, data from 1778 herpes zoster patients studied within 72 h of rash onset in four clinical trials of the antiviral agent famciclovir were examined. Univariate and multivariate analyses indicated that greater acute pain severity was significantly associated with greater age, female sex, greater rash severity, the presence of a prodrome, and primary involvement of non‐trigeminal dermatomes. These results demonstrate that three of the established risk factors for PHN – older age, greater rash severity, and the presence of a prodrome – are also associated with more severe acute pain assessed soon after rash onset in patients with herpes zoster. The results of this study are consistent with the recommendation that herpes zoster patients who are older, who have had a prodrome, or who have severe rash or severe acute pain should be targeted for interventions designed to prevent PHN.

Famciclovir: Efficacy in Zoster and Issues in the Assessment of Pain

When acyclovir was introduced in the early 1980’s, we saw a remarkable change in the treatment of herpes virus infections such as genital herpes simplex virus (HSV) infections, ocular HSV infections and varicella zoster virus (VZV) infections (chickenpox and shingles) in both the normal and immunocompromised host.1 The now widespread use of acyclovir is a reflection of its safety and tolerability, and clinical trial data has demonstrated its utility in the treatment of human disease. As a consequence, human suffering has been alleviated and, in some cases, mortality reduced (e.g., neonatal HSV infections and herpes simplex enciphalitis).2,3