Until the 1980s serological tests for antibodies to HSV were rarely useful to diagnosis and not routinely used in clinical practice. The older IgM serologic assay could not differentiate between antibodies generated in response to HSV-1 or HSV-2 infection. However, a glycoprotein G-specific (IgG) HSV test introduced in the 1980s is more than 98% specific at discriminating HSV-1 from HSV-2.
At the other end of the spectrum, there is a possibility of a herpetic flare up taking a sinister turn and leading to herpetic encephalitis. It is estimated to affect at least 1 in 500,000 individuals per year. The mechanism of this is not fully understood, but it is believed that the infection occurs through direct transmission of the virus via nerves from other parts of the body to the brain. In such cases, a person may complain of fever, headache, and lethargy, followed by confusion or delirium. In some cases, some people even develop seizures. This requires immediate medical attention and treatment.
HSV-1 has been proposed as a possible cause of Alzheimer's disease. In the presence of a certain gene variation (APOE-epsilon4 allele carriers), HSV-1 appears to be particularly damaging to the nervous system and increases one's risk of developing Alzheimer's disease. The virus interacts with the components and receptors of lipoproteins, which may lead to its development.
Herpes is transmitted via skin-to-skin contact, not through blood or saliva. Cullins explains that someone with HSV can be shedding the herpes virus without having an outbreak (known as asymptomatic virus shedding), and infect somebody that way. Suppressive antiviral medications, like acyclovir or valacyclovir, inhibit HSV replication, which decreases shedding but does not completely eliminate it, says Johnston.
Doctors prescribe suppressive treatment if a person experiences more than six recurrences in a year. In some cases, a doctor my recommend that the individual takes daily antiviral treatment indefinitely. The aim here is to prevent further recurrences. Although suppressive treatment significantly reduces the risk of passing HSV to a partner, there is still a risk.
People who have had HSV-1 are less likely to contract HSV-2 than those who have not. Previous exposure to HSV-1 also decreases the severity of an HSV-2 outbreak. Reoccurrence of the virus is common, and the virus can be active yet asymptomatic. These infections are more likely to be contracted since the person isn’t aware the virus is active. Studies have shown that 50 percent of the cases of sexual transmission of the virus occurred during asymptomatic infections.
A doctor will base a presumptive diagnosis on information provided by the patient and on the physical examination. The characteristic appearance of the herpes sores leaves little doubt about the diagnosis, so the typical appearance of the sores is key to the diagnosis. This appearance helps distinguish oral herpes from oral thrush, shingles, gonorrhea, and syphilis. In addition, chapped or sunburned lips can resemble oral herpes, but the tissue stain (Tzanck smear, see below) shows no virus-induced cell changes. Further testing is usually not necessary but is sometimes done.