Snapshot A 22-year-old man presents to his primary care physician for a sore throat and oral lesions. He said his symptoms began a few days ago and have progressively worsened. Initially, his symptoms were associated with fever and submandibular lymphadenopathy. He endorses having sexual intercourse with multiple female partners without the use of condoms. Physical examination is notable for a perioral papulovesicular lesion without any genital lesions. Introduction Classification an enveloped, double-stranded linear DNA virus from the Herpesviridae family Epidemiology incidence more commonly affects the oral mucosa Transmission respiratory secretions saliva Pathogenesis herpes simplex virus (HSV) 1 inoculates the mucosal surfaces of skin and makes its way to the sensory dorsal root ganglion, where it lies dormant reactivation of HSV 1 from dormancy leads to vesicle formation, pustulations, ulcerations, and scabbing involving the mucosa of the face mouth lips oropharynx eye various triggers can reactivate HSV 1 from dormancy emotional stress immunodeficiency fever menstruation sunlight trigeminal nerve manipulation dental extractions Associated conditions HSV encephalitis Bell palsy erythema multiforme ezcema herpeticum esophagitis Prognosis lesions are typically self-limiting in healthy patients herpetic episodes are more severe and have a longer duration in immunocompromised patients Presentation Symptoms/physical exam gingivostomatitis keratoconjunctivitis esophagitis fever pharyngitis painful vesicular lesions Studies Making the diagnosis this is a clinical diagnosis based on the patient's history and appearance perioral papulovesicular lesions Tzank smear demonstrates multinucleated giant cells (intranuclear eosinophilic Cowdry A inclusions) seen in HSV 1, HSV 2, and VZV infections Real-time HSV PCR assay confirms the diagnosis Differential Aphthous ulcers differentiating factors these ulcers are never preceded by vesicles and only appear on nonkeratinized mucosal surfaces (e.g., inner surfaces of the lips and buccal mucosa Treatment Medical acyclovir, famciclovir, or valacyclovir indications immunocompromised patients patients with frequent outbreaks Complications HSV encephalitis Pneumonitis HSV esophagitis