<unk>  infection occurs when the<unk>  simplex virus comes into contact with oral mucosal tissue or abraded skin of the mouth. Infection by the type 1 strain of<unk>  simplex virus (HSV-1) is most common; however, cases of oral infection by the type 2 strain are increasing. Oral HSV-2 shedding is rare, and "usually noted in the context of first episode genital<unk> ." In general, both types can cause oral or genital<unk> . Cold sores are the result of the virus reactivating in the body. Once HSV-1 has entered the body, it never leaves. The virus moves from the mouth to remain latent in the central nervous system. In approximately one-third of people, the virus can "wake up" or reactivate to cause disease. When reactivation occurs, the virus travels down the nerves to the skin where it may cause blisters (cold sores) around the lips or mouth area. In case of<unk>  zoster the nose can be affected. Cold sore outbreaks may be influenced by stress, menstruation, sunlight, sunburn, fever, dehydration, or local skin trauma. Surgical procedures such as dental or neural surgery, lip tattooing, or dermabrasion are also common triggers. HSV-1 can in rare cases be transmitted to newborn babies by family members or hospital staff who have cold sores; this can cause a severe disease called neonatal<unk>  simplex. The colloquial term for this condition, "cold sore" comes from the fact that<unk>  is often triggered by fever, for example, as may occur during an upper respiratory tract infection (i.e. a cold). People can transfer the virus from their cold sores to other areas of the body, such as the eye, skin, or fingers; this is called autoinoculation. Eye infection, in the form of conjunctivitis or keratitis, can happen when the eyes are rubbed after touching the lesion. Finger infection <unk> ic whitlow) can occur when a child with cold sores or primary HSV-1 infection sucks their fingers. Blood tests for<unk>  may differentiate between type 1 and type 2. When a person is not experiencing any symptoms, a blood test alone does not reveal the site of infection. Genital<unk>  infections occurred with almost equal frequency as type 1 or 2 in younger adults when samples were taken from genital lesions.<unk>  in the mouth is more likely to be caused by type 1, but (see above) also can be type 2. The only way to know for certain if a positive blood test for<unk>  is due to infection of the mouth, genitals, or elsewhere, is to sample from lesions. This is not possible if the afflicted individual is asymptomatic. The body's immune system typically fight the virus.
Herpes labialis
Impetigo
Lentigo simplex
Infectious mononucleosis
Herpes simplex
Aphthous stomatitis
Tinea faciei
Herpangina