A patient, aged 28 years, presents with complaints of one day of very itchy lesions around her lips.
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The skin finding identified in this patient is an example of an orolabial lesion caused by the herpes simplex virus (HSV). There are two closely related types of HSV, both of which most commonly present with mucocutaneous infections.
HSV type 1 (HSV-1) is mostly associated with orofacial disease, and HSV type 2 (HSV-2) is usually associated with genital and perigenital infections. However, both viruses can infect oral and genital areas.
By the age of 30, approximately 80% of individuals have been exposed to HSV-1. HSV-1 is transmitted primarily through direct contact with contaminated saliva or other infected secretions, and the incidence of recurring labial herpes is greatest during childhood, when as many as 60% of children are exposed to the virus. These rates increase with age and reduced socioeconomic status.
Both serotypes of HSV are members of the herpesviridae family of double-stranded DNA viruses. Infection manifests as lesions in the epidermis, usually involving mucosal surfaces, as well as spread to the nervous system.
In most HSV-1 primary infections, the virus replicates in the oropharyngeal epithelium, before infecting local nerve endings and ascending via peripheral sensory axons to the trigeminal ganglion, where it resides in a period of latency before reactivation.
With reactivation, the virus migrates from the ganglion along the axon back to the epidermis, causing the recurring lesions often seen in infection.
Individuals without apparent lesions may still transmit the virus due to asymptomatic viral shedding. Sunlight, hyperthermia, local trauma, and numerous psychological stressors influence reactivation.
Severely immunocompromised patients can develop disseminated, chronic, and drug-resistant infections.
Presentation and Course
The majority of primary orolabial infections are asymptomatic, although primary infections in some individuals may present with more severe symptoms than their recurring episodes, often with systemic signs and symptoms such as fever, malaise, myalgias, and cervical lymphadenopathy.
Symptoms in primary infection typically occur three to seven days after exposure and have a variable presentation; for instance, a mononucleosis-like exudative pharyngitis may be seen in young adults, although the most common sites of invasion are the mouth and lips.
Reactivation of the virus after primary infection typically involves the vermillion border of the lips, and is often preceded by prodromal symptoms such as pain, burning, or itching at the site of the subsequent eruption. However, patients may experience both prodromal symptoms and eruptions in the absence of the other.
The lesions are typically painful grouped vesicles on an erythematous base, which may progress to pustules, erosions, and ulcerations that have a characteristic scalloped border. Crusting and resolution is usually seen within two to six weeks.
Following genital-oral contact, HSV-2 can cause a primary orolabial infection indistinguishable from those caused by HSV-1, although HSV-2 orolabial infections are much less likely to reactivate.
The diagnosis of herpes is largely clinical based the appearance of grouped vesicles which may coalesce to form a scalloped border.
Polymerase chain reaction (PCR) testing is more sensitive than viral culture and is more accurate in later stages of the lesions. Direct fluorescent antibody testing is a rapid but it is less sensitive. Viral culture is not a sensitive test.
Many HSV infections are self-limited and may require no treatment at all. Primary orolabial infections that are protracted, highly symptomatic, or complicated may be treated with oral antiviral medications such as acyclovir.
Modest benefits have been seen in the treatment of recurrent episodes of herpes labialis, particularly when the medication is administered in the prodromal or early lesion stages. Suppressive antiviral treatment for herpes labialis has had mixed results, but is a potential option for individuals concerned about transmission to a partner.
Jonathan Whitehouse, BS, is a medical student at Baylor College of Medicine.
Adam Rees, MD, a graduate of the David Geffen School of Medicine at UCLA, practices dermatology in Los Angeles.
- Bolognia J, Jorizzo J, Rapini R. “Chapter 80 – Human Herpesviruses.” Dermatology. St. Louis, MO: Mosby/Elsevier. 2008. Print.
- Freedberg IM et al.”Chapter 193 – Herpes Simplex.” Fitzpatrick’s Dermatology In General Medicine. 6thed. New York: McGraw-Hill; 2003. Print.