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Herpes simplex - oral - Management
What advice should I give about preventing cold sores recurring?

  • Minimize the impact of trigger factors:
    • Consider the use of sunblock lip balm (SPF 15 or greater) to help reduce outbreaks if sunlight is a potential trigger.
  • Inform the individual that prophylactic use of topical antivirals is ineffective.
  • Advise that, for immunocompetent people, the benefits of suppressive (continuous) therapy with oral antivirals are small and do not justify the routine use of long-term treatment. Episodic treatment might be preferred and more convenient (e.g. for those with 1–2 mild episodes per year).
  • For people with frequent or severe episodes, or for immunocompromised individuals (e.g. with HIV), prophylactic oral antiviral treatment may be helpful. Specialist advice should be sought.
Basis for recommendation
  • Minimize the impact of trigger factors:
    • In practice, trigger factors for cold sores are difficult to avoid or to modify (e.g. fatigue, psychological stress, trauma, and menstruation).
    • However, randomized controlled trials (RCTs) involving ultraviolet (UV) light induced cold sores indicate that sunblock may reduce recurrences if sunlight is a potential trigger factor [Worrall, 2006].
      • One small crossover RCT (n = 38) found sunblock (SPF 15) prevented lesions developing after UV exposure, while 71% of the placebo group developed lesions [Rooney et al, 1991]. Another small crossover RCT (n = 19) found a lower incidence of recurrence in the sunscreen group (5% recurrence) than placebo (58% recurrence) (p < 0.01) [Duteil et al, 1998].
  • Prophylactic use of oral antivirals:
    • There is limited evidence to support long-term prophylactic therapy in immunocompetent individuals. Treatment can increase the risk of systemic adverse effects. Compliance with therapy is important.
      • A small, double-blind placebo-controlled RCT indicated that aciclovir may delay the onset of cold sores. However the study was small (n = 22 healthy adults) and 18% of the aciclovir group dropped out due to adverse effects [Rooney et al, 1993].
      • The combined results of 2 double-blind RCTs (n = 98 healthy adults) found that prophylactic oral valaciclovir therapy delays recurrence of cold sores compared with placebo [Baker and Eisen, 2003]. However, it is uncertain if the populations of the two separate trials were matched. The study provides no details regarding randomization procedure, severity of recurrences and symptoms, and treatment compliance, nor any period effect.
    • There is little evidence to favour long-term suppressive (continuous) therapy over episodic (as required) treatment with oral antivirals:
      • CKS found one open-label, crossover RCT (76 adults enrolled but only 55 completed study) which found modest benefits with suppressive therapy (valaciclovir 1 g daily) compared with episodic treatment (valaciclovir 2 g twice daily, during attack) when treatments were taken for 6 months (mean number of cold sore episodes per 120 days of follow up: 0.49 episode for suppressive therapy vs. 1.1 for episodic therapy) [Gilbert, 2007]. However, the authors cautioned that results should be interpreted in the context of a significant period effect, which was not explained by the time of the year.
    • Prophylaxis regimens for patients who experience mild outbreaks 1 to 2 times a year are not recommended [Woo and Challacombe, 2007].
    • However, prophylactic therapy may be of use for those with frequent, severe episodes, or immunocompromised individuals who are at risk of developing severe complications [Arduino and Porter, 2006; Woo and Challacombe, 2007]. Specialist advice should be sought as the optimal timing and dose of treatment are uncertain and can vary in different situations [Arduino and Porter, 2006].
  • Prophylactic use of topical antivirals:
    • There is no good evidence to suggest that topical antivirals (aciclovir or penciclovir) can prevent or delay recurring cold sores.
      • Two small trials (n = 18 and n = 23) found no, or a modest, benefit with aciclovir compared with placebo [Fawcett et al, 1983; Gibson et al, 1986; Esmann, 2001].
      • One larger randomized, double-blind trial (undertaken in seven ski resorts, n = 191 treated) found no significant difference between topical aciclovir 5% cream and placebo in the number of people who experienced lesions during the treatment period [Raborn et al, 1997].
    • Given that frequent daily application is required, long-term continuous suppression with a topical antiviral preparation might be impractical [Esmann, 2001].

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