Pathogenesis of recurrent herpes simplex labialis. IV. Maturation of lesions within 8 hours after onset and implications for antiviral treatment.

In order to define precisely the development of recurrent herpes simplex labialis, we studied 122 untreated or placebo-treated patients who were first seen when their lesions were less than 24 hours old. Subjects were divided into three groups with lesion ages of 0 to 8, 9 to 16, or 17 to 24 hours. Lesion pain, area, and virus titer were determined for each group at the time of the first clinic visit and again on the following day, and the change in lesion severity between visits was examined. The proportion of patients with increasing or decreasing lesion values was markedly influenced by lesion age. Among 0- to 8-hour-old lesions, area, pain, and virus titer increased in 27%, 21%, and 39% of the subjects, respectively, compared to 10%, 6%, and 0% among those lesions were 17 to 24 hours old at the first visit. A decrease in lesion area, pain, and virus titer was seen in 14%, 24%, and 12% of 0- to 8-hour-old lesions, compared with 35%, 65%, and 54% of the lesions in the 17- to 24-hour age group (p = 0.03, 0.006, and 0.0002). The majority of patients in each age group had mature lesions that remained unchanged or decreased in severity between visits. The possible benefits of antiviral chemotherapy to established lesions are limited because only a small number of untreated patients have progressive disease.