Herpes Simplex Virus-1 (HSV-1) is the etiological agent responsible for herpetic oropharyngeal diseases. The virus itself is notable for its ubiquity, with 70-90% of the global population carrying the virus. Primary infection is usually asymptomatic. However, when symptomatic, primary infection is highly variable and can be marked by ulcerative and vesicular lesions, fever, sore throat, givgivostomatitis, edema, localized lymphadenopathy, malaise, and/or loss of apetite. The incubation period usually lasts roughly four days, but can last anywhere from two to 12 days.
Contraction of HSV-1 usually occurs in children under the age of five years. Primary infection in children is uncommon. However, when symptomatic disease occurs in children, it involves the buccal and gingival mucosa and is thus referred to as herpes simplex gingivostomatitis. The primary HSV infection often causes a clinical illness lasting 2-3 weeks, with the patient having a fever of 101-104 degrees Fahrenheit. In such cases, vesicular lesions appear in the mouth and on the face. These lesions are often referred to as intraoral gingival lesions. Acquired later in life, HSV-1 causes a pharyngitis and a mononuleosis-like primary infection. The adult primary infection is marked by ulcerative tonsilar lesions on an erythematous base. Submandibular lymphadenopathy is also common.
Recurrent orolabial lesions occur most often at the vermillion border of the lip. Their recurrence is preceded by a six hour prodrome during which a tingling sensation is felt on the lip border. This prodrome is followed 24-48 hours later by vesicle formation that lasts 48 hours. The number of pustules usually numbers between three and five. The total area of involvement is limited to less than 100 square millimeters. Healing is complete within 8-10 days. The factors precipitating recurrences are poorly defined but include fever, stress, exposure to UV light, Vitamin C and menstruation.