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Herpes simplex - oral - Making a diagnosis
Primary infection

  • Primary infection refers to first-time exposure to herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) [Leflore et al, 2000].
  • Many primary infections do not cause symptoms or signs [Jensen et al, 2004], and therefore will not present to a healthcare professional.
  • Symptomatic primary infection usually presents as gingivostomatitis in children, and as pharyngotonsillitis or a mononucleosis (glandular fever) -type illness in adults [Kolokotronis and Doumas, 2006].
  • Prodromal symptoms include fever, nausea, malaise, headache, and irritability [Kolokotronis and Doumas, 2006; Torres, 2007].
  • Symptoms of active infection include a painful mouth and throat, salivation, and drooling [Kolokotronis and Doumas, 2006; Torres, 2007].
  • Signs include [Hirsch, 1995; Kolokotronis and Doumas, 2006; Gonsalves et al, 2007; Torres, 2007]:
    • Vesicles which can affect the border of the lip with the skin, and the pharyngeal and oral mucosa (soft palate, buccal mucosa, tongue, and floor of the mouth).
    • Breaking down of the vesicles into small, red lesions. These enlarge and develop central ulcerations covered by yellow/grey membranes.
    • Halitosis.
    • Cervical and submandibular lymphadenopathy.
    • Fever.
    • Dehydration.
  • In people who are immunocompromised, infection can be severe, with large, necrotizing lesions which cover large areas [Torres, 2007].
  • Tests are not usually necessary in immunocompetent people, as history and examination will usually confirm the diagnosis.
    • Herpes simplex virus can be detected, and the type determined, using viral culture from skin vesicles. Early in the infection, 80–90% of viral cultures from untreated lesions are positive, but the false-negative rate increases 2 days after the lesions have appeared [Torres, 2007].
    • Polymerase chain reaction (PCR) is an alternative diagnostic test, which in general detects HSV 3–4 times more often than cultures [Esmann, 2001; Woo and Challacombe, 2007].
    • The availability of tests may vary in primary care, therefore check with the local laboratory.

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