These herpes viruses enter the body through small cuts, abrasions, or breaks in the skin or mucous membranes. The incubation period for herpes simplex infections is about three to six days. Transmission (spread) of the virus is person to person and more likely to occur if blisters or lesions are present. The majority enter after an uninfected person has direct contact with someone carrying the virus (either with or without noticeable lesions). Simply touching an infected person is often the way children get exposed. Adolescents and adults frequently get exposed by skin contact but may get their first exposure by kissing or sexual contact (oral and/or genital contact), especially for HSV-2. Statistical studies suggest that about 80%-90% of people in the U.S. have been exposed to HSV-1 and about 30% have been exposed to HSV-2. Usually, the contagious period continues until lesions heal. Some people (estimated from 30%-50%) occasionally shed herpes virus while having few or no associated symptoms or signs.
Pain, sore lips, burning sensation, tingling, or itching occurs at the infection site before the sores appear. These are the early symptoms (prodrome). Sometimes these symptoms happen prior to the appearance of sores, bumps, pimple-like lesions, or blisters (herpes or herpetic stomatitis). Thereafter, clusters or groups of painful blisters (also termed fever blisters) or vesicles erupt or ooze with a clear to yellowish fluid that may develop into a yellowish crust. These blisters break down rapidly and appear as tiny, shallow gray ulcers on a red base. Fever blisters are smaller than canker sores. A few days later, they become crusted or scabbed and appear drier and more yellow.
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.
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.
Although it's rare, pregnant women can pass on the herpes infection to their child. This can result in a serious and sometimes deadly infection in the baby. That's why taking steps to prevent an outbreak at time of delivery is recommended starting at 34 weeks into the pregnancy. If you have signs of an active viral infection when it's time to deliver, your doctor will likely recommend a cesarean section for delivery.
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
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.
The U.S. Centers of Disease Control and Prevention explains that pain, itching or tingling in the area where the rashes will eventually appear will occur at least one to five days before the rashes are seen. Once these rashes are visible, they scab for around seven to 10 days and heal within two to four weeks.29 Aside from rashes, symptoms of shingles include fever, chills, headaches, fatigue and an upset stomach.30,31
How to get rid of a cold sore The herpes simplex virus that causes cold sores, often on people’s mouths, is highly contagious and a lifelong infection with no cure. Learn about how to treat cold sores when they appear, including anti-viral tablets and creams and home remedies, plus the life cycle of the virus, and how to prevent its spread. Read now