Herpes simplex labialis (HSL), often referred to as "cold sores" or "fever blisters," is a common infectious disease affecting millions of people in the United States. The infection leads to the development of painful lesions on the lips and bordering areas; and in rare cases they may also appear on the chin, face, and nose. Pharmacists are frequently consulted on how to treat this condition, and it is important for them to understand the disease as well as prevention and treatment available.
HSL is caused by herpes simplex virus type 1 (HSV-1). HSV type 2 (HSV-2) causes genital herpes, although both types may actually be responsible for cold sores.1 Cold sores can sometimes be confused with canker sores, which are not caused by a virus and are not contagious but may be bacterial in nature.2 It is estimated that approximately 80% of the population carries HSV-1, but only about 20% will experience cold sore outbreaks.3
The initial infection usually occurs in childhood or before the age of 20 years4 and may actually cause no symptoms or mouth lesions. After a person is infected, the virus remains dormant in the trigeminal ganglia until the virus reactivates. Although key triggers have an association with viral reactivation, a cause-effect relationship has not yet been established. Cold sores have a physical, social, and emotional impact: people with cold sores experience pain and discomfort, as well as feelings of embarrassment, which ultimately may lead to social isolation.
After a person has first been exposed to the virus, symptoms may not appear for several weeks. During subsequent outbreaks, some people experience a prodrome episode, which involves "warning symptoms" such as burning, itching, pain, or tingling. This may occur within 8 to 12 hours after reactivation of the virus. A few patients may also experience fever, headache, malaise, lymphadenopathy, and sore throat.5 Approximately 25% to 30% of patients, however, do not experience a prodrome; in such patients the first sign is red bump or papule.
The stages of a cold sore have been well documented. The initial papule develops into small pustules (filled with clear fluid) which coalesce to form a blister. The blister then bursts to form an ulcer. A soft crust forms over the ulcer and hardens to form a scab. The scab may crack and bleed, finally falling off and leaving behind redness and swelling. If left untreated, the healing process takes approximately 8 to 10 days.
Because the virus lies dormant in the body, recurrent lesions are usually a result of triggers:
Treatment is aimed at shortening the duration of the outbreak, which can be accomplished with disease-modifying agents, or at controlling the pain and other symptoms.5
Disease-Modifying Medications. Prescription antiviral agents, such as topical acyclovir (Zovirax) and penciclovir (Denavir) are FDA-approved to treat the virus. Systemic agents available include famciclovir (Famvir), acyclovir (Zovirax), and valacyclovir (Valtrex). These agents do not have curative properties, but they can help to reduce the duration of the episode.5
A cell-entry blocker, Abreva (10% docosanol in a moisturizing base) is the only OTC medication approved by the FDA to shorten healing time and duration of symptoms. Docosanol is incorporated into the cell membrane to help block the cold sore virus from fusing with the lip cell. Since HSV-1 needs to penetrate a cell to reproduce, docosanol helps prevent viral replication.
Symptomatic Treatments. Many products available over the counter are effective and safe in relieving the symptoms associated with cold sores:
Clinical trials have evaluated the efficacy and safety of the OTC cell entry blocker Abreva and shown significant reduction in the duration of symptoms as well as healing time.* It is important to use Abreva as soon as the first symptoms (redness, itching, tingling) appear. Because of Abreva?s unique mode of action, it is hypothesized that starting treatment at the first sign may actually reduce the extent of infected cells. In fact, patients should be counseled to carry Abreva at all times in the event of a cold sore episode, especially if exposure to a key trigger is anticipated. Abreva is now available in pump form that is unique to the category. This is advantageous because it is portable and dispenses the right amount of medication to help speed healing and reduce symptom duration. The Abreva pump is convenient to carry and fits in the purse or pocket. This allows the patient to treat a cold sore outbreak at the very first sign of symptoms, leading to a better disease outcome.
For those 12 years of age and over, Abreva should be applied 5 times a day until the lesion heals. Always remember to recommend that patients wash their hands before and after application, and avoid applying Abreva directly inside the mouth or near the eyes. If the lesions are still present after 10 days, the patient should consult a physician.
* Sacks SL et al. Clinical efficacy of topical docosonal 10% cream for herpes simplex labialis: a multicenter, randomized, placebo-controlled trial. J Am Acad Dermatol. 2001; 45:222-230.
Key Points to Battle HSV|
1. Pray WS. Oral problems. In: Nonprescription Product Therapeutics. 2nd ed. Baltimore, Md: Lippincott Williams & Wilkins: 2006:56-80.
2. Gossel TA. Healing Cold Sores: Facts Attitudes and Treatment Advances. Power-Pak CE, September 2001.
3. Oral Health Guide: Mouth Sores. Zila Pharmaceuticals Inc.
4. Medical Encyclopedia: Herpes labialis (oral Herpes simplex). Available at: www.nlm.nih.gov/medlineplus/print/ency/article/000606. htm Accessed June 21, 2007.
5. Weinberg MA, Maloney WJ. Treatment of common oral lesions. US Pharm. 2007:32:3.
6. Sacks SL, Thisted RA, Jones TM, et al. Clinical efficacy of topical docosanol 10% cream for herpes simplex labialis: a multicenter, randomized, placebo-controlled trial. J Am Acad Dermatol. 2001;45:222-230.
7. Health Consultants. Releev. Available at: www.naturalhealthconsult.com/Monographs/ViraMedx.html. Accessed July 4, 2007.
8. Abreva. Available at: http://www.abrevapharmacist.com/about_cold_sores_lifecycle.aspx. Accessed July 4, 2007.
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