Abstract and Introduction
Herpes labialis is a frequently occurring viral infection of the lips and oral mucosa. Recurring lesions are induced by viral reactivation and replication, but the symptoms leading to morbidity, such as pain and inflammation, are immune-mediated. The introduction of 5% acyclovir/1% hydrocortisone in a topical cream (Xerese™) represents a therapeutic strategy directed at both of these pathogenic processes. Applied at the onset of prodromal symptoms, this combination treatment has a good safety profile and is more effective in reducing healing time than antiviral or anti-inflammatory agents alone. Although it was US FDA-approved for herpes labialis in 2009, Xerese™ has only recently been approved for use in Canada in October 2013. Herein, we review the basic science and clinical studies that support the efficacy of this topical combination acyclovir-hydrocortisone product in treating herpes labialis and examine its safety profile, as well as touch upon other therapies that have been shown to be effective in treating this common viral condition.
Herpes labialis (colloquially known as "cold sores") is a common viral infection characterized by vesicular lesions of the lips and oral mucosa. It is estimated to affect 1 in 5 Canadians annually and is associated with a negative stigma that can lead to depression, fear of rejection, and isolation for infected individuals during an outbreak. Herpes labialis is mostly caused by the herpes simplex virus-1 (HSV-1), which enters the nerve during primary infection and remains latent in the ganglionic neuron for the rest of the individual's life. Periodically, the virus travels back down the nerve to the skin and replicates, producing a clinical episode of reactivated HSV-1 infection. Intralesional viral replication is halted by the host immune response approximately 7 days after primary infection and 3 days after recurrent infection; however, inflammation secondary to immune defense is also the cause of redness, swelling, and tenderness that is characteristic of herpes labialis lesions. As a result, although viral clearance happens rapidly following reactivation, the lesion often takes 7–10 days to heal completely.
Since the pathogenesis of herpes labialis is both viral- and immune-mediated, it is not surprising that administration of exclusively antiviral drugs has limited effects on the clinical parameters of the disease. Therefore, medications demonstrating dual mechanisms via inhibition of viral replication and modulation of the inflammatory response to facilitate healing, indicate a more successful therapeutic approach. Such an agent was introduced by Valeant Pharmaceuticals, consisting of 5% antiviral acyclovir plus 1% anti-inflammatory hydrocortisone (ACHC) in a topical cream formulation (Xerese™). Although it has been FDA-approved in the US for the treatment of recurrent herpes labials since 2009, authorization for Xerese™ in Canada was not officially granted until October 2013. In light of this recent Canadian approval, we review the data supporting the efficacy of this topical combination therapy and discuss the details regarding its clinical use, specifically incorporating our experience in prescribing ACHC for the past half-decade.
Skin Therapy Letter. 2014;19(3) © 2014 SkinCareGuide.com