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."
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.
Neonatal herpes simplex is a HSV infection in an infant. It is a rare but serious condition, usually caused by vertical transmission of HSV-1 or -2) from mother to newborn. During immunodeficiency, herpes simplex can cause unusual lesions in the skin. One of the most striking is the appearance of clean linear erosions in skin creases, with the appearance of a knife cut. Herpetic sycosis is a recurrent or initial herpes simplex infection affecting primarily the hair follicles.:369 Eczema herpeticum is an infection with herpesvirus in patients with chronic atopic dermatitis may result in spread of herpes simples throughout the eczematous areas.:373
Human herpes virus 1 (HHV1) is also known as herpes simplex virus 1 (HSV1). It is typically the cause of cold sores around the mouth. HHV1 can also lead to infection in the genital area causing genital herpes usually through oral-genital contact, such as during oral sex. HHV1 infections are contagious and are usually spread from skin-to-skin contact with an infected person through small breaks in the skin or mucous membrane. The HHV1 virus is more likely to be spread through things like sharing eating utensils, razors, and towels from a person who has an active lesion.
Traditionally, it was assumed that HSV-1 strictly caused oral sores and blisters, whereas HSV-2 caused genital and/or rectal sores and blisters. However, the virus- or perhaps just our understanding of the virus itself- has evolved in such a way that doctors now recognize that either HSV-1 or HSV-2 can cause genital and/or rectal sores, albeit with HSV-2 causing the majority of sores in the genital or rectal areas.
A person may show symptoms within days after contracting genital herpes, or it may take weeks, months, or years. Some people may have a severe outbreak within days after contracting the virus while others may have a first outbreak so mild that they do not notice it. Because of these possibilities, it can be difficult for people to know when and from whom they may have contracted the virus.