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Herpes Simplex
Genital herpes simplex virus (HSV) infections are discussed in.
HSV infections are caused by two different virus types (HSV-1 and HSV-2), which can be distinguished by laboratory and office tests. HSV-1 is generally associated with oral infections, and HSV-2 is associated with genital infections. HSV-1 genital infections and HSV-2 oral infections are becoming more common, possibly as a result of oral-genital sexual contact. Both types seem to produce identical patterns of infection. Many infections are asymptomatic, and evidence of previous infection can be detected only by an elevated IgG antibody titer. HSV infections have two phases: the primary infection, after which the virus becomes established in a nerve ganglion; and the secondary phase, characterized by recurrent disease at the same site. The rate of recurrence varies with virus type and anatomic site. Genital recurrences are nearly 6 times more frequent than oral-labial recurrences; genital HSV-2 infections recur more often than genital HSV-1 infections; and oral-labial HSV-1 infections recur more often than oral HSV-2 infections.
Many primary infections are asymptomatic and can be detected only by an elevated IgG antibody titer. Like most virus infections, the severity of disease increases with age. The virus may be spread via respiratory droplets, direct contact with an active lesion, or contact with virus-containing fluid such as saliva or cervical secretions in patients with no evidence of active disease. Symptoms occur from 3 to 7 or more days after contact. Tenderness, pain, mild paresthesias, or burning occurs before the onset of lesions at the site of inoculation. Localized pain, tender lymphadenopathy, headache, generalized aching, and fever are characteristic prodromal symptoms. Some patients have no prodromal symptoms. Grouped vesicles on an erythematous base appear and subsequently umbilicate ( The virus replicates at the site of primary infection. Virons are then transported by neurons via retrograde axonal flow to the dorsal root ganglia, and latency is established in the ganglion. Local skin trauma (e.g., ultraviolet light exposure, chapping, abrasion) or systemic changes (e.g., menses, fatigue, fever) reactivate the virus, which then travels down the peripheral nerves to the site of initial infection and causes the characteristic focal, recurrent infection. Recurrent infection is not inevitable. Many individuals have a rise in antibody titer and never experience recurrence. The prodromal symptoms of itching or burning, lasting 2 to 24 hours, resemble those of the primary infection. Within 12 hours, a group of lesions evolves rapidly from an erythematous base to form papules and then vesicles. The dome-shaped, tense vesicles rapidly umbilicate. In 2 to 4 days, they rupture, forming aphthaelike erosions in the mouth and vaginal area or erosions covered by crusts on the lips and skin. Crusts are shed in approximately 8 days to reveal a pink, reepithelialized surface. In contrast to the primary infection, systemic symptoms and lymphadenopathy are rare unless there is secondary infection. The frequency of recurrence varies with anatomic site and virus type. The laboratory diagnosis of herpes simplex is covered in, which discusses sexually transmitted viral infections. A number of measures can be taken to relieve discomfort and promote healing; these are described in the following sections. The appropriate use of topical, oral, and intravenous antiviral agents is outlined ( Transmission is dependent on intimate, personal contact with someone excreting HSV. Gingivostomatitis and pharyngitis are the most frequent manifestations of first-episode HSV-1 infection. Infection occurs most commonly in children between ages 1 and 5 years. The incubation period is 3 to 12 days. Although most cases are mild, some are severe. Sore throat and fever may precede the onset of painful vesicles occurring anywhere in the oral cavity or on the face (see Recurrences average two or three each year but may occur as often as 12 times a year. Oral HSV-1 infections recur more often than oral HSV-2 infections. A number of treatment modalities have been used for herpes on the vermilion border. Oral acyclovir, famciclovir, and valacyclovir can be used to treat the primary infection and episodic recurrences and for suppression (see Corticosteroids in combination with an oral antiviral agent may be beneficial for episodic treatment of herpes labialis. Famciclovir (500 mg tid for 5 days) and topical fluocinonide (0.05% tid for 5 days) significantly reduced lesion size and pain. Topical treatments include penciclovir cream (Denavir), n -docosanol cream (Abreva), and acyclovir cream. Abreva is an over-the-counter drug. The cream is applied frequently (e.g., every 2 hours while awake) at the first sign of prodromal symptoms or erythema. These creams may shorten an episode of herpes labialis by a few hours or a day and may not be worth the high cost. Many patients believe that these creams are effective and prefer them to oral medication. The lips should be protected from sun exposure with an opaque cream such as zinc oxide or with sun-blocking agents incorporated into a lip balm (Chap Stick). A cool water or Burrow's solution compress decreases erythema and debrides crusts to promote healing. Lubricating creams may be applied if the lips become too dry. Herpes simplex may appear on any skin surface ( Herpes simplex of the fingertip (herpetic whitlow) ( Cutaneous herpes in athletes involved in contact sports is transmitted via direct skin-to-skin contact. This is a recognized health risk for wrestlers. Herpes simplex of the buttock area is much more common in women ( Herpes simplex of the lumbosacral region or trunk may be very difficult to differentiate from herpes zoster; the diagnosis becomes apparent only at the time of recurrence. Oral antiviral drugs are useful for suppressive therapy, particularly for recurrent fingertip and buttock infections. Eczema herpeticum (Kaposi's varicelliform eruption) is the association of two common conditions: atopic dermatitis and HSV infection. Certain atopic infants and adults may develop the rapid onset of diffuse cutaneous herpes simplex. The severity of infection ranges from mild and transient to fatal. The disease is most common in areas of active or recently healed atopic dermatitis, particularly the face, but normal skin can be involved. The disease in most cases is a primary HSV infection. In one third of the patients in a particular study, there was a history of herpes labialis in a parent in the previous week. Eczema herpeticum of the young infant is a medical emergency; early treatment with acyclovir can be life saving.
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Clinical Dermatology
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