The sequelae of herpes zoster

Background: The last 40 years was a period during which the incidence of herpes tester appears to have increased substantially. Objective: To determine whether the risk of complications of herpes tester has changed during the last 40 years. Methods: The automated medical records of a health maintenance organization were screened for diagnosis codes suggesting herpes tester and potentially complicated cases of tester. The predictive value of a herpes zoster diagnosis was calculated from sampling full-text records. Records of all patients with codes suggesting complications were reviewed in full. Results: Of 859 individuals with herpes tester who met the eligibility criteria, 101 were identified who experienced at least I complication, corresponding to a 60-day risk of 12%. Corrected for the sensitivity of the complication-finding strategy, the risk estimate was 14%. Risk increased markedly with age, with those older than 64 years having more than 6 times the risk of complications of those younger than 25 years (odds ratio, 8.3; 95% confidence interval, 2.5-29.3). Trigeminal distribution of rash and the presence of certain conditions associated with immune compromise appeared to increase risk. Conclusions: The apparent increase in the incidence of herpes tester was not accompanied by a change in the risk of specific or overall complications in a population-based sample. Advanced age and other conditions associated with waning cellular immunity may confer an increased risk of experiencing a complicated course of herpes zoster.