The natural history of recurrent facial-oral infection with herpes simplex virus.

Fifty-seven episodes of facial-oral infections with herpes simplex virus (HSV) (cold sores) were studied in 41 ambulatory patients. Patients were examined within 24 hr of the onset of symptoms and for five consecutive days. Clinical parameters were assessed, lesion size was measured, and daily cultures for virus were performed. HSV was isolated in 61% of the episodes and was HSV type 1 in all cases. Serum neutralizing antibody to HSV was measured initially and 21 days after the onset of symptoms. All patients had antibody initially, but a fourfold or greater rise in titer was seen in only four patients. Lesion size and stage of healing were compared in patients with virus-positive episodes and those with virus-negative episodes. These two groups were found to be clinically distinct. Virus-positive lesions were larger, and the rate of healing was slower. This finding provides the first clinical correlation associated with the presence of HSV in cold sores.