The relationship between pityriasis rosea, seasonal factors, and other herpetic infections: A time series analysis

Abstract

Background: Data on seasonal variation and viral etiology in Pityriasis rosea (PR) have been conflicting. The aim of this study was to investigate the association of PR and other herpetic infections, taking seasonal changes into account. Methods: The data were collected retrospectively from electronic health registry systems in Sivas in the Central Anatolia region of Turkey between 2008 and 2016. According to their clinical types, other herpetic infections were investigated. Environmental factors such as humidity, temperature, and rainfall for the relevant period were added into the model. Time series methods (augmented Dickey–Fuller unit root test and regression analysis) were used in the analysis. Results: A total of 1207 PR patients were included in the study. The number of PR patients was calculated to be 0.462 times that of the same period in the previous year. The incidence of PR increased significantly when the rate of infections caused by varicella-zoster virus decreased and the rate of infections caused by herpesvirus Type 1 and humidity increased (P < 0.05). Conclusion: Environmental factors such as humidity are important in the emergence of the PR. Furthermore, the incidence of PR may be inversely affected by varicella-zoster infections contrary to the relationship between PR and herpesvirus Type 1 infections.

Keywords

• Epidemiology
• herpesvirus
• Pityriasis rosea
• seasonal variation
• varicella