Labial herpes is an infection of the lip by the herpes simplex virus. It is characterized by inflammation of the affected area, followed by painful, fluid-filled blisters on the lip. People who suffer from the disease carry the herpes simplex virus for life, and it is dormant when there are no symptoms. It is also possible for people to carry the herpes simplex virus without ever exhibiting symptoms.
The blisters caused by this type of herpes are commonly called fever blisters or cold sores, because they are more likely to appear when a person with herpes simplex already has an infection from another source, such as the upper respiratory tract infection that often accompanies a cold. An outbreak begins with tingling or redness of an area on the lips or on the border between the lips and face. Next, small, round blisters form and remain for up to three weeks. Labial herpes, as well as any herpes simplex infection, is passed through skin-to-skin contact with an infected individual, or contact between the skin and the virus itself. Herpes simplex is most often contracted when the person carrying the virus is having an outbreak, which begins before the appearance of blisters.
Labial herpes is often accompanied by herpes symptoms elsewhere on the face or mouth. If it affects both the face and mouth, the condition is called orofacial herpes. Herpes of the mouth may be called herpetic stomatitis. In addition to labial herpes, herpetic stomatitis is characterized by gingivostomatitis or inflammation of the cheeks and gums, as well as sores or lesions inside the mouth. Other possible symptoms include difficulty swallowing, pharyngitis or sore throat, swollen lymph nodes, and glandular fever.
There are two species of herpes simplex virus. Herpes simplex virus I is most often responsible for cold sores, although cases have been caused by herpes simplex virus II as well. Herpes simplex virus II is more often associated with genital herpes, which causes similar symptoms to labial herpes, but on the genitals, and is transmitted through sexual contact. It is possible for both types of herpes to be contracted through oral-genital contact. However, if a person has a history of fever blisters caused by herpes simplex virus I, he or she has formed antibodies that will prevent other infections, such as genital infections, caused by the same herpes simplex virus species.