Case Study

April 1, 2002
A 21-year-old female visited a general dentist for evaluation of multiple blisters on her lips.

By Joen Iannucci Haring, DDS, MS

A 21-year-old female visited a general dentist for evaluation of multiple blisters on her lips.


The patient first noted the blisters one day earlier. She reported that, since the onset, the blisters had increased in number. In addition, she stated that the lesions were painful. When questioned about other signs and symptoms, the patient stated that her glands (lymph nodes) felt swollen. The patient denied the presence of any intraoral lesions or the history of a previous episode.

A review of the patient's medical history revealed no significant findings. At the time of the dental visit, the patient was taking acetaminophen to relieve the pain associated with the oral lesions. No other medications were reported.


Examination of the head and neck areas revealed several enlarged and tender submandibular lymph nodes. The patient's blood pressure was within normal limits. No other lesions were apparent in the head and neck region. Oral examination revealed multiple, small vesicles on the upper and lower vermilion of the lips. Some of the vesicles appeared to cross the mucocutaneous junction and affect the adjacent skin. No intraoral lesions were noted.

Clinical diagnosis

Based on the clinical information presented, which of the following is the most likely diagnosis?

  • Hand, foot, and mouth disease
  • Herpangina
  • Herpetiform aphthous ulcers
  • Acute herpetic gingivostomatitis
  • Recurrent herpes labialis


• Recurrent herpes labialis


Recurrent herpes labialis (RHL) – also referred to as a cold sore or fever blister – is an extremely common oral lesion. An estimated 100 million episodes of RHL occur annually in the United States. Consequently, it is not uncommon to see this lesion routinely in dental practice. RHL is a viral lesion; it is the reactivation of the herpes simplex virus (HSV).

Oral herpetic infections present in one of two clinically evident patterns: primary infection and recurrent infection. The initial infection of an individual without antibodies to HSV is termed the primary infection. This primary infection occurs one time only, and any person without immunity to HSV is susceptible to such an infection. The recovery from a primary infection with HSV differs from many viral infections in that the virus is not completely eliminated from the body. Instead, the virus travels along the sensory nerve fibers of the trigeminal nerve and resides in the nerve ganglia until it is reactivated.

It is the "reactivation" of this latent virus that causes a recurrent infection. HSV is unique in that, once an individual is infected, the virus remains within the host for life.

Clinical features

RHL may occur in children or adults. Clinical symptoms do not include fever or malaise; however, lymphadenopathy is often present. Stimulating factors include exposure to intense sunlight, trauma, and stress. The location of RHL includes the vermilion of the lip and adjacent skin. The number of lesions present with an episode of RHL is variable and the associated discomfort usually is not severe.

Prior to the initial presentation of RHL, a prodromal period occurs indicating the onset of the lesion. Symptoms may include burning, tingling, and itching. Following the prodromal period, erythema, swelling, and vesicle formation occur. The vesicles are small, fluid-filled elevations that contain the herpes virus. As RHL progresses, clusters of vesicles coalesce and then rupture to form shallow ulcerations.

Following the formation of ulcerations, a crust develops. Healing occurs following the crust formation and usually is complete within seven to 10 days.

RHL in the vesicular stage is infectious. Any activity that exposes a person to direct mucocutaneous contact with cold sores, or exposes a person to saliva containing HSV may result in the transfer of the virus. There is no documented evidence of HSV transmission from inanimate objects such as toilet seats or from swimming pools and hot tubs.


The diagnosis of RHL is most often established based on the clinical signs, symptoms, and patient history of recurrence. Laboratory confirmation may be required in instances of a questionable diagnosis. HSV isolation from tissue culture inoculated with the fluid from vesicular lesions is the preferred laboratory test. Cytologic smear techniques and tissue biopsy also may be used to establish a diagnosis.


There is no cure for RHL. Palliative medications can be recommended to alleviate symptoms, but do not speed the healing time. Patients should be informed that autoinoculation is a potential problem and instructed to avoid mechanical rupture of the vesicles in order to prevent the spread of the virus to adjacent areas and to the mucous membranes of the nose and eyes.

Although a variety of over-the-counter and homemade remedies have been used in an attempt to speed the healing of these lesions, none are dramatically effective. In addition, topical antiviral prescription medications are of limited value, and systemic antiviral therapy is not recommended for RHL in an immunocompetent individual.

OTC medications

Two recent additions to current topical therapies for RHL warrant further independent investigation. In 2000, the FDA approved Abreva (10 percent n-docosonal cream). This OTC product has been reported in a limited number of studies to shorten the mean healing time by up to three days. Another product, a mixture of "quaternary ammonium chlorides, dimethyl carbonal, and other chemicals" has been marketed through dental and dermatology offices to treat RHL. Until this treatment has been scientifically tested and proven to be effective, its use cannot be recommended.

Topical prescription medications

Acyclovir ointment in polyethylene glycol, a topical prescription medication, is of limited benefit to treat RHL because its base component is believed to prevent significant absorption. In contrast, prescription penciclovir cream (Denavir) is supplied in a base that allows absorption when applied to the lips. The use of this product has been shown to result in a minimal reduction in healing time (duration of the lesion only decreased by less than one day).

Systemic medications

The FDA does not support the use of systemic acyclovir for RHL in immunocompetent individuals. Most cases of RHL are mild and infrequent and do not justify the regular use of systemic antiviral medication. The careless use of antiviral medication such as acyclovir for RHL may result in subsequent acylovir-resistant HSV infections.

There has been some limited success with systemic antiviral medications (for example, acyclovir, valacyclovir, and famciclovir) when prescribed to prevent RHL. Although research by a variety of investigators have produced variable results, these medications appear to be capable of minimizing recurrences when administered prophylactically.

Joen Iannucci Haring, DDS, MS, is an associate professor of clinical dentistry, Section of Primary Care, The Ohio State University College of Dentistry.