Herpes Simplex Virus 1 & 2

  • Herpes Simplex Infection May Raise Risk of Alzheimer's

    Herpes Simplex Infection May Raise Risk of Alzheimer's

    Orofacial HSV infections affect 15% to 30% of the population. This photo shows a primary outbreak of herpes simplex around the mouth. Primary infections can range from subclinical to severe, with fever, headache, malaise, anorexia, pain, lymphadenopathy and edema. Secondary infections are usually milder.

  • Genital HSV is the most common sexually transmitted infection (STI) in both men and women, but as many as 90% don’t know they are infected because their symptoms are too mild to notice or mistaken for another condition. The incubation period for HSV-2 is 3 days to 2 weeks after exposure. Clinical recurrence occurs on average 3 to 4 times a year, but some patients experience monthly outbreaks.

  • Symptomatic genital herpes is characterized by a burning and itching sensation in the genitals, followed by blistering. In women who contract the disease, the cervix is infected 80% to 90% of the time during primary infection. Cervical infection alone is rarely symptomatic, but because the cervix is not sensitive to pain, infection may pass unnoticed.

  • HSV skin lesions usually appears as small blisters or sores around the mouth, nose, genitals, buttocks, and lower back, though infections can develop almost anywhere on the skin. This photo shows a close-up of lesions on the upper eyelid in a 20-year-old male patient due to HSV-1.

  • This photo shows HSV-1 lesions on the buttock of a five-year-old girl — also called sacral herpes simplex. In children diagnosed with HSV-2, consider sexual abuse as a possibility.

  • This photo depicts HSV-1 lesions on the elbow of an 11-year-old girl.

  • Herpetic whitlow is an intensely painful infection of the hand involving 1 or more fingers that typically affects the terminal phalanx. HSV-1 causes approximately 60% of cases, whereas HSV-2 accounts for the remaining 40%.

  • Chronic and/or severe HSV infections can also be seen in immunocompromised patients, including transplant recipients, HIV-positive individuals, and those with lymphoma, leukemia and renal failure. The most common presentation in this category is chronic enlarging ulcerations, lesions at multiple sites and/or cutaneous dissemination.

  • Serologic testing for HSV has limited value in acute clinical diagnosis because of the time delay for seroconversion following initial infection. Of patients who develop seropositivity, 65% do so within six weeks, while approximately 20% do not make antibodies for six months.

  • Viral cultures and PCR provide more accurate results during active phases of HSV, as the bulk of the viruses hide from the host

  • Acyclovir, valacyclovir and famciclovir are the most commonly used agents for treating HSV infections. While all three drugs decrease the duration and severity of illness and viral shedding, they have no effect on nonreplicating viruses, nor do they eliminate the virus from the ganglia. All three agents appear to have equivalent clinical efficacy. Peniciclovir cream 1% (Denavir) is available to treat herpes labialis only.

  • A wide disparity exists between the public and medical community regarding the significance of herpes infections. Although treatment options exist, respondents in one survey considered contracting herpes as worse than breaking up with a significant other, getting fired from a job, or failing a course in school. Be sure to provide adequate counseling to help patients put their diagnosis in perspective.

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The majority of recurrent oral herpes cases are caused by herpes simplex virus type 1 (HSV-1) and the majority of genital herpes cases are caused by HSV-2. However, HSV-1 is the most common cause of new genital herpes in teens and college students, and accounts overall for about 40% of all new genital herpes infections.

Differentiating between the two types of infection using either type specific swab testing, preferably PCR, or type specific IgG antibody testing, is very important because HSV-1 genitally recurs less, is shed less, and presents far less risk of transmission to others than HSV-2. Antibody testing is not appropriate with possible new infection.

Fifty seven percent of Americans between 14 and 49 have HSV-1, and 16% of the same group has HSV-2 infection. HSV infection is a persistent and chronic infection of the sensory ganglia with a varying, unpredictable degree of skin expression. This slideshow will highlight variations in presentation and provide more information about diagnosis and treatment.


  1. American Sexual Health Association. Herpes Resource Center. Available online at http://www.ashastd.org/std-sti/Herpes.html.
  2. Burkhardt CG. “A Guide to Recognizing and Treating Herpes.” Clinical Advisor. November 2006.
  3. Wu IB, Schwartz RA. Herpetic whitlow. Cutis. Mar 2007;79(3):193-6.

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