Antivirals and Vaccines
1 | Antiviral Treatments
Herpes Simplex Virus (Cold Sores)
Cold sores, also known as fever blisters, are the most commonly seen oral viral infection. One of nine known human pathogens in the herpes virus family, HSV-1 causes cold sores that are characterized by an initial infection, with persistence in nerve cell bodies that reside in ganglia. These lesions are contagious, which makes them dangerous to patient and provider.
The vesicles rupture about day two, releasing countless viruses. Prompt treatment, ideally at the prodromal stage, with topical or systemic antiviral drugs will mitigate the severity and duration of the outbreak. Treatment might differ based on the severity of the infection and the immunocompetency of the patient. For patients who are immunocompromised, a systemic drug such as acyclovir or valacyclovir is preferred.
In cases of mild infection, a topical prescription form of antiviral medication plus a numbing agent is recommended. Other treatments can be found over-the-counter (OTC) at pharmacies (Refer to table 1 on page 42). Docosanol cream, which is available OTC, provides a barrier that can be helpful. It is notable, however, that this barrier does not prevent viral shedding, thus handwashing and avoiding physical contact with the ulceration remain important. Finally, Benzalkonium chloride combined with benzocaine which is a non-prescription product, is also available from dental supply sources.
Infections around the eyes should be treated by an ophthalmologist. Dental healthcare workers should consider rescheduling a patient with vesicles or draining exudate.
• Disinfectants such as Betadine, possibly mixed with alcohol as a drying agent, have proven helpful for some patients. Betadine is an effective disinfectant for the exudate.
• Antimicrobial mouthwashes such as hydrogen peroxide, or chlorhexidine can be used to prevent plaque accumulation especially when brushing is painful.
• Non-pharmacological treatments such as bed rest, increased fluid intake, and avoidance of sun exposure may be helpful.
(NOTE: There is a genital strain of the virus, Herpes simplex type 2 (HSV-2), which also can occur orally. It is in another group of the nine member herpes family. Treatment is similar to that of HSV-1.)
Aphthous Ulcers (Canker Sores)
Aphthous ulcers or canker sores are another common oral condition, but are probably not viral in origin. Antiviral therapies are not effective in treating aphthous ulcers. Differentiation from cold sores is important to properly treat these ulcers. Often a traumatic event precedes the prodromal phase, similar to the herpetic eruption. In addition, aphthous ulcers have been associated with the frequent use of NSAIDs.
Aphthous ulcers occur as single or multiple intraoral lesions, generally on nonkeratinized mucous membranes and not on attached mucosa, the hard palate or the tongue dorsum. They are not infectious, pointing away from a microbial origin. Also, pointing away from an infectious cause is the fact that they lack a vesicular state. Some have noted that smokers are less likely to experience these lesions, ostensibly due to thicker epithelium.
Aphthous ulcers resolve spontaneously but may benefit from topical application of anesthetics or barriers (See Chapter 8: Oral Lesions and Corticosteroids). Many therapies have been suggested for relief of symptoms. There is no vaccine nor curative drug. Specifically, antiviral drugs are not effective. Likewise, antimicrobial agents do not affect these ulcerations, except in preventing secondary infection in patients who are immunocompromised. It has been reported that regular use of the amino acid lysine as a supplement has preventative action. In addition, toothpaste that does not contain sodium lauryl sulfate (SLS) could be recommended to patients with recurrent aphthous ulcers.
Herpes Zoster Virus
The herpes zoster virus causes two relatively common oral conditions, chickenpox and shingles. Like many viral conditions, there is an initial infection (chickenpox), followed by quiescent viral residence within nerve ganglia. Now, many children avoid this problematic disease through vaccination in early childhood. Protection is often not effective for the lifetime of the individual, leading to recurrence in adulthood, known as shingles.
Some evidence exists that people with herpes zoster are more prone to stroke from cerebral infarct.