Herpes

Herpes Disorders Recurrence Transmission and prevention Diagnosis Epidemiology Treatment

Recurrence

Following active infection herpes viruses establish a latent infection in sensory and autonomic ganglia of the nervous system. The double-stranded DNA of the virus is incorporated into the cell physiology by infection of the nucleus of a nerve's cell body. HSV latency is static—no virus is produced—and is controlled by a number of viral genes, including Latency Associated Transcript (LAT).

Many HSV infected people experience recurrence within the first year of infection. Prodrome precedes development of lesions. Prodromal symptoms include tingling (paresthesia), itching, and pain where lumbosacral nerves innervate the skin. Prodrome may occur as long as several days or as short as a few hours before lesions develop. Beginning antiviral treatment when prodrome is experienced can reduce the appearance and duration of lesions in some individuals. During recurrence fewer lesions are likely to develop, lesions are less painful, and lesions heal faster (within 5–10 days without antiviral treatment), than those occurring during the primary infection. Subsequent outbreaks tend to be periodic or episodic, occurring on average four to five times a year when not using antiviral therapy.

The causes of reactivation are uncertain, but several potential triggers have been documented. Physical or psychological stress can trigger an outbreak of herpes. Changes in the immune system during menstruation may play a role in HSV-1 reactivation. Concurrent infections, such as viral upper respiratory tract infection or other febrile diseases, can cause outbreaks. Reactivation due to infection is the likely source of the historic terms cold sore and fever blister.

Other identified triggers include: local injury to the face, lips, eyes, or mouth, trauma, surgery, radiotherapy, and exposure to wind, ultraviolet light, or sunlight.

The frequency and severity of recurrent outbreaks may vary greatly between patients. An immunity to the virus is built over time; immunocompromised individuals may experience episodes that are longer, more frequent and more severe. Antiviral medication has been proven to shorten the frequency and duration of outbreaks. Outbreaks may occur at the original site of the infection or in close proximity to nerve endings that reach out from the infected ganglia. In the case of a genital infection, sores can appear at the original site of infection or near the base of the spine, the buttocks, back of the thighs.