The correct diagnosis is zoster (shingles), a reactivation of a latent infection with varicella-zoster virus (VZV).
Zoster has a lifetime incidence of 10 o 20 f the population, with prevalence increasing with age. The prodromal phase is characterized by severe neuralgia. Fever, malaise, and headache are normally present one to four days before formation of cutaneous or mucosal lesions, which present opaque white vesicles measuring 1 mm to 4 mm and set on an erythematous base, which rupture to form shallow ulcerations in two to four days.
Usually, the lesions are confined to a distinct dermatome, and terminate at the midline of the mouth. Vesicles may be seen on the skin but are rarely identified intraorally because they last only a brief period of time before rupturing to form shallow ulcers. As the virus travels down the nerve, the pain intensifies in the area of epithelium innervated by the second or third division of the trigeminal nerve. The exanthem typically resolves within three weeks in otherwise healthy individuals.
Herpes simplex can cross the midline and tends to present with similar shallow ulcerations, but with a more focal area of involvement: extraorally on the skin or vermilion zone of the lip and intraorally on the gingiva and hard palate.
Aphthous ulcers (canker sores) present as single or multiple painful intraoral ulcerations limited to movable mucosa. They may have a unilateral distribution, but will not be found on the hard palate or attached gingiva.
The Tzanck smear is the most rapid and least expensive test if the sample can be taken within three days of the start of vesicle formation. Viral culture takes at least 24 hours. Direct staining of cytologic smears with fluorescent monoclonal antibodies for VZV also gives a rapid diagnosis. Patients with active vesicular lesions can spread the infection to immunocompromised hosts, and if the patient is a healthcare provider, he/she should take a leave of absence from work.
Antiviral therapy (acyclovir, famciclovir, or valacyclovir) administered in the first 72 hours can shorten the length and severity of the acute episode.
Acknowledgment: Case presented by Logical Images, Inc.
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