Incidence and Time Trends of Herpes Zoster in Rheumatoid Arthritis: A Population-Based Cohort Study

Herpes zoster or shingles is a common cutaneous disorder caused by the reactivation of latent varicella-zoster virus dormant in the cranial nerve or dorsal root ganglia. It usually manifests as a dermatomal distribution of a vesicular eruption that can cause significant morbidity (1). Herpes zoster is known to be more frequent in patients with conditions that depress cell-mediated immunity, including malignancy, HIV, transplantation, immunosuppressive disorders and treatment with immunosuppressants (2). The overall rate of herpes zoster in patients with rheumatoid arthritis (RA) is increased compared to the general population, with a greater risk in individuals using traditional disease modifying antirheumatic drugs (DMARDs) or biologic therapies (3). Use of prednisone in RA is an important predisposing factor for herpes zoster, and its use in conjunction with DMARDs increases the risk beyond that seen with the DMARDs alone (4). Many unanswered questions remain regarding the relationship between RA and reactivation of herpes zoster, and how RA related disease features, treatment and herpes zoster prevention measures might be addressed to avoid recurrent and complicated herpes zoster in these patients. We performed a population-based study to assess the incidence, time trends, risk factors and severity of herpes zoster in a well defined population of patients with RA. This information should serve the eventual goal of identifying possible strategies that could be employed to minimize the risk of development of herpes zoster in patients with RA.