Herpes virus type 1 (HSV-1) is the cause of cold sores or fever blisters around the mouth. Usually, the sores or blisters can show up on the outside of the mouth or on the lips. But sometimes, they can be inside the mouth, on the face, nose, cheeks or fingers. HSV-1 can also lead to infection of the genitals, called genital herpes. This occurs when you have a cold sore and perform oral sex on another person. HSV-1 infections are highly contagious. Apart from oral-genital contact, they can be spread through skin-to-skin contact. If you come into contact with a person or a thing that carries HSV-1, you will be likely to get it, too. Often, people get HSV-1 from kissing someone with a cold sore or when they share eating utensils, razors, or towels.
There are two types of herpes simplex viruses (HSV), they are termed HSV-1 and HSV-2. These two viruses have distinctly different DNA, and both cause oral and genital lesions. However, HSV-1 causes about 80% of all oral lesions and only about 20% of genital lesions while HSV-2 causes the reverse (about 80% genital and 20% oral). Studies also suggest that in adolescents, up to 40% of genital herpes is caused by HSV-1 because of reported increased oral/genital contact (transmission by oral sex).
A herpes infection is caused by the herpes simplex virus (HSV). It has 2 main types, including HSV-1 and HSV-2. While HSV-1 can cause oral herpes, HSV-2 can be responsible for genital herpes. Oral herpes is also known as cold sores or fever blisters. It mainly occurs on the lips, around the mouth. Genital herpes is usually referred to as herpes. It mostly affects the genitals and anal area. Genital herpes is considered to be a sexually transmitted disease. It’s extremely contagious and can be spread through sexual intercourse.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
The cell this virus targets is the B lymphocyte. These cells mature in the bone marrow and are a type of mononuclear leukocyte cells - white blood cells with a one-lobed nucleus. The incubation period for the Epstein – Barr Virus (EBV) is about 30 to 50 days, and patients typically have enlarged lymph nodes and spleens. Some patients have signs of hepatitis.

Although the exact cause of Bell's palsy—a type of facial paralysis—is unknown, it may be related to reactivation of HSV-1.[23] This theory has been contested, however, since HSV is detected in large numbers of individuals having never experienced facial paralysis, and higher levels of antibodies for HSV are not found in HSV-infected individuals with Bell's palsy compared to those without.[24] Antivirals may improve the condition slightly when used together with corticosteroids in those with severe disease.[25]
There’s herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). “HSV-1 and HSV-2 are different but closely related viruses,” says Dr. Christine Johnston, MPH, who is the Associate Medical Director of the Virology Research Clinic at the University of Washington. Johnston explains that both are transmitted through close mucosal or skin contact with infected secretions. HSV-1 primarily causes oral outbreaks, also known as cold sores, and HSV-2 usually causes genital outbreaks. But HSV-1 can also cause genital outbreaks through oral-to-genital contact, according to the CDC. According to Johnston, genital HSV-1 is less likely to recur than HSV-2, and there’s less asymptomatic shedding (transmitting the virus without realizing it) with HSV-1 than with HSV-2.

These drugs may stop viral replication in the skin but do not eliminate HSV from the body or prevent later outbreaks (HSV reactivation). These drugs are used more frequently with HSV-2 infections. Most investigators suggest consulting an infectious-disease expert when HSV-infected people need hospitalization. Research findings suggest laser treatments may speed healing and lengthen the time before any sores reappear.


Primary orofacial herpes is readily identified by examination of persons with no previous history of lesions and contact with an individual with known HSV infection. The appearance and distribution of sores is typically presents as multiple, round, superficial oral ulcers, accompanied by acute gingivitis.[39] Adults with atypical presentation are more difficult to diagnose. Prodromal symptoms that occur before the appearance of herpetic lesions help differentiate HSV symptoms from the similar symptoms of other disorders, such as allergic stomatitis. When lesions do not appear inside the mouth, primary orofacial herpes is sometimes mistaken for impetigo, a bacterial infection. Common mouth ulcers (aphthous ulcer) also resemble intraoral herpes, but do not present a vesicular stage.[39]
A 2004 study in the New England Journal of Medicine found that suppressive therapy decreases the risk of HSV-2 transmission from symptomatic, infected partners to uninfected partners by 48%. So “the risk of transmission is significantly reduced, but cannot be eliminated even with suppressive therapy,” Johnston explains, and she stresses that the virus can be passed along even without signs or symptoms.
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