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Herpes simplex - oral - Management
Should I advise use of a topical antiviral to treat cold sores?
- Advise that the benefits of topical antivirals (aciclovir or penciclovir) are small and require treatment to be initiated at the onset of symptoms (erythema or prodromal stage) before vesicles appear.
- Reassure the individual that the cold sores will usually resolve within 7–10 days even without treatment.
- If topical antiviral therapy is desired, remind the individual that:
- Topical antivirals only affect the course of the current episode. They do not cure the individual or prevent future episodes of cold sores.
- Treatment needs to be initiated at the onset of symptoms before vesicles appear.
- Compliance with treatment is important, as antivirals need to be applied frequently for a minimum of 4–5 days.
- Topical antivirals are widely available (without prescription) to treat future recurrences, if the individual finds them helpful. This can help to minimize the delay before starting treatment.
- Seek specialist advice when managing people who are immunocompromised (including people with HIV) with cold sores.
Clarification / Additional information
Basis for recommendation
- These recommendations are pragmatic advice, based on published expert review and evidence from randomized controlled trials (RCTs).
- Most episodes of cold sores are generally mild and self limiting and can be treated symptomatically. For further information, see Self care advice
- Mechanism of action:
- Evidence from double-blind placebo-controlled RCTs involving topical antiviral creams (aciclovir 1% cream or penciclovir 1% cream) indicate that the benefits of topical treatment are small:
- Although an earlier RCT found no benefit [Shaw et al, 1985], aciclovir 5% cream has been shown in a larger study to reduce the mean duration of an episode and pain by approximately 0.5 days [Spruance et al, 2002]. For penciclovir 1% cream, a reduction of about 0.6–1 day was found in 2 RCTs [Raborn, 1996; Spruance et al, 1997; Raborn et al, 2002].
- However, treatments with topical aciclovir or penciclovir do not appear to have an impact on the development of lesions, the number of participants developing lesion pain, or the proportion of people with aborted lesions [Raborn, 1996; Spruance et al, 1997; Raborn et al, 2002; Spruance et al, 2002].
- A literature review of cold sores RCTs cautioned that 'significant' results should be interpreted in the context of statistical (not clinical) significance [Woo and Challacombe, 2007].
- Timing of treatment:
- In double-blind placebo-controlled RCTs, treatments with topical aciclovir or penciclovir were initiated within 1 hour of onset of signs or symptoms of a cold sore episode (erythema or prodromal stage) [Raborn, 1996; Spruance et al, 1997; Raborn et al, 2002; Spruance et al, 2002].
- It is expected that the maximum clinical benefit from antiviral therapy is gained when treatment is started early because most viral replication occurs within the first 48 hours. Early initiation of antiviral therapy terminates virus replication and hence limits the subsequent epithelial damage responsible for the development of visible lesions [Esmann, 2001].
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