The Origin of the Idea That Herpes Labialis Is of Prognostic Importance in Bacterial Meningitis

Objective:The aim of the work was to study the origin of the idea that herpes labialis (HL) in patients with pneumonia and meningitis was believed to be of prognostic importance. Background:HL is caused by a primary infection or reactivation of herpes simplex type I. In the past, it has been related to pneumonia and meningitis; moreover, HL was believed to be of prognostic importance. Methods:A selection of 19th- and 20th-century textbooks and referred articles was consulted. The relation between meningitis and herpes, type of meningitis, and attributed diagnostic and prognostic importance were studied. In addition, the HL-pneumonia association was studied. Results:The Strasbourg physician Charles-Polydore Forget was the first to describe the HL-meningitis association in 1843. Tourdes (1843), Drasche (1859), and Salomon (1864) attributed a favorable prognostic importance to the HL-meningitis relation. In a comprehensive monograph (1866), August Hirsch, although confirming the association, denied the prognostic importance through critical analysis of the data. Few authors attributed a diagnostic importance to the occurrence of HL, suggesting meningococcal meningitis. Conclusions:The HL-meningitis relation, but not the prognostic importance, has been mentioned in most neurological textbooks since then. In contrast to meningitis, in which a prognostic attribution of HL was only a short-lived 19th-century idea, the favorable prognostic importance of HL in pneumonia continued to be described until the 1950s. A possible protective effect of herpesviruses has been found in recent years. One could speculate that the disappearance of the prognostic HL-pneumonia relation could be related to the introduction of antibiotics in the late 1940s.