Herpes Simplex Virus Type 1 infection: overview on relevant clinico‐pathological features*

Herpes Simplex Virus Type 1 (HSV‐1) is a nuclear replicating enveloped virus, usually acquired through direct contact with infected lesions or body fluids (typically saliva). The prevalence of HSV‐1 infection increases progressively from childhood, the seroprevalence being inversely related to socioeconomic background. Primary HSV‐1 infections in children are either asymptomatic or following an incubation period of about 1 week gives rise to mucocutaneous vesicular eruptions. Herpetic gingivostomatitis typically affects the tongue, lips, gingival, buccal mucosa and the hard and soft palate. Most primary oro‐facial HSV infection is caused by HSV‐1, infection by HSV‐2 is increasingly common. Recurrent infections, which occur at variable intervals, typically give rise to vesiculo‐ulcerative lesions at mucocutaneous junctions particularly the lips (herpes labialis). Recurrent HSV‐1 infection within the mouth is uncommon in otherwise healthy patients, although in immunocompromised patients, recurrent infection can be more extensive and/or aggressive. The diagnosis of common herpetic infection can usually be based upon the clinical history and presenting features. Confirmatory laboratory diagnosis is, however, required when patients are, or may be, immunocompromised.