Herpes, whether on the mouth or genitals, is caused by a family of over 70 related viruses. These viral infections cause small, fluid-filled blisters to develop on the skin and mucous membranes. There are actually eight different types of herpes simplex viruses that both children and adults can acquire, but two are by far the most common: HSV-1 and HSV-2.
Herpes infection can cause sores or breaks in the skin or lining of the mouth, vagina, and rectum. This provides a way for HIV to enter the body. Even without visible sores, having genital herpes increases the number of CD4 cells (the cells that HIV targets for entry into the body) found in the lining of the genitals. When a person has both HIV and genital herpes, the chances are higher that HIV will be spread to an HIV-uninfected sex partner during sexual contact with their partner’s mouth, vagina, or rectum.
Genital herpes is contracted through sexual activity, and may show symptoms around the genital area (anus, buttocks, thigh, penis, vulva, etc.). Additionally, people with HIV can experience significantly worse symptoms of herpes. See a doctor if your partner has herpes, or if you notice any unusual sores on your body. How do you know if you have herpes? Read more in our Diagnosing Herpes section here.
Herpesviral encephalitis and herpesviral meningitis Herpes simplex encephalitis (HSE) is a rare life-threatening condition that is thought to be caused by the transmission of HSV-1 either from the nasal cavity to the brain's temporal lobe or from a peripheral site on the face, along the trigeminal nerve axon, to the brainstem. Despite its low incidence, HSE is the most common sporadic fatal encephalitis worldwide. HSV-2 is the most common cause of Mollaret's meningitis, a type of recurrent viral meningitis.
Pain, itching and the appearance of sores called lesions are common symptoms of genital herpes. Lesions may appear inside or outside the vagina, and on or around the penis. In both women and men, these sores may appear in and around the anus.6 Lesions typically appear from two days to two weeks after you first get infected with the virus, and will take seven to 14 days or more to heal.7
As with almost all sexually transmitted infections, women are more susceptible to acquiring genital HSV-2 than men. On an annual basis, without the use of antivirals or condoms, the transmission risk of HSV-2 from infected male to female is about 8–11%. This is believed to be due to the increased exposure of mucosal tissue to potential infection sites. Transmission risk from infected female to male is around 4–5% annually. Suppressive antiviral therapy reduces these risks by 50%. Antivirals also help prevent the development of symptomatic HSV in infection scenarios, meaning the infected partner will be seropositive but symptom-free by about 50%. Condom use also reduces the transmission risk significantly. Condom use is much more effective at preventing male-to-female transmission than vice versa. Previous HSV-1 infection may reduce the risk for acquisition of HSV-2 infection among women by a factor of three, although the one study that states this has a small sample size of 14 transmissions out of 214 couples.
Herpes simplex type 1, which is transmitted through oral secretions or sores on the skin, can be spread through kissing or sharing objects such as toothbrushes or eating utensils. In general, a person can only get herpes type 2 infection during sexual contact with someone who has a genital HSV-2 infection. It is important to know that both HSV-1 and HSV-2 can be spread even if sores are not present.
HSV infection causes several distinct medical disorders. Common infection of the skin or mucosa may affect the face and mouth (orofacial herpes), genitalia (genital herpes), or hands (herpetic whitlow). More serious disorders occur when the virus infects and damages the eye (herpes keratitis), or invades the central nervous system, damaging the brain (herpes encephalitis). People with immature or suppressed immune systems, such as newborns, transplant recipients, or people with AIDS, are prone to severe complications from HSV infections. HSV infection has also been associated with cognitive deficits of bipolar disorder, and Alzheimer's disease, although this is often dependent on the genetics of the infected person.
Genital herpes is passed on by skin-to-skin contact during vaginal, oral or anal sex, or by sharing sex toys. You can get genital herpes even if there are no visible sores or blisters, and once you have the virus, there is no cure. 'Herpes is more likely to be passed on just before, during or straight after an outbreak, as herpes blisters and sores are highly infectious,' says O’Sullivan.
Some people have recurrent outbreaks with the so-called “classic” blister-like herpes lesions that crust over, or with painful sores. In recurrent herpes, however, this process usually takes about half the time it does in first episodes. In addition, many people have very subtle forms of recurrent herpes that heal up in a matter of days. And lastly, herpes is capable of reactivating without producing any visible lesions (asymptomatic reactivation).
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.
Recurrent outbreaks of genital herpes may happen, with some patients having four to six outbreaks in the span of a year. Compared to the first infection, subsequent recurrences are less painful and occur in shorter periods than the first infection. There are some patients, however, who don’t have another outbreak for many years or even once more during their lifetime.11
The herpes virus is probably the most well-known virus after influenza (the flu) or the common cold. What most people don’t know is that this nasty little virus can take several different forms, eight to be exact. The most common form of the herpes virus is chicken pox, which is called varicella-zoster. Herpes simplex is the sexually transmitted version of the virus.
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.
Oral herpes is a viral infection mainly of the mouth area and lips caused by a specific type of the herpes simplex virus. Oral herpes is also termed HSV-1, type 1 herpes simplex virus, or herpes labialis. The virus causes painful sores on the upper and lower lips, gums, tongue, roof of the mouth, inside the cheeks or nose, and sometimes on the face, chin, and neck. Infrequently, it may cause genital lesions. It also can cause symptoms such as swollen lymph nodes, fever, and muscle aches. People commonly refer to the infection as "cold sores."
Although it’s not caused by either the HSV-1 or HSV-2 virus, herpes zoster falls under the umbrella of herpes diseases. Also known as shingles, it’s an infection caused by the varicella-zoster virus, and is characterized by the development of painful skin rashes on one side of the face or body.23 These rashes are red patches of fluid-filled blisters that tend to crack easily.24,25
It should not be confused with conditions caused by other viruses in the herpesviridae family such as herpes zoster, which is caused by varicella zoster virus. The differential diagnosis includes hand, foot and mouth disease due to similar lesions on the skin. Lymphangioma circumscriptum and dermatitis herpetiformis may also have a similar appearance.
Herpes infection can be passed from you to your unborn child before birth but is more commonly passed to your infant during delivery. This can lead to a potentially deadly infection in your baby (called neonatal herpes). It is important that you avoid getting herpes during pregnancy. If you are pregnant and have genital herpes, you may be offered anti-herpes medicine towards the end of your pregnancy. This medicine may reduce your risk of having signs or symptoms of genital herpes at the time of delivery. At the time of delivery, your doctor should carefully examine you for herpes sores. If you have herpes symptoms at delivery, a ‘C-section’ is usually performed.