When we say, “herpes” many of us are thinking about genital herpes, famously known as an incurable inconvenience. But there is more to it than being just a sexually transmitted infection. There are multiple ways that herpes can transmit but genital herpes is usually picked up from sexual contact. Apart from that, herpes can be transmitted when sharing an environment with someone who has the infection as well.
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.
It should not be confused with conditions caused by other viruses in the herpesviridae family such as herpes zoster, which is caused by varicella zoster virus. The differential diagnosis includes hand, foot and mouth disease due to similar lesions on the skin. Lymphangioma circumscriptum and dermatitis herpetiformis may also have a similar appearance.
A doctor will base a presumptive diagnosis on information provided by the patient and on the physical examination. The characteristic appearance of the herpes sores leaves little doubt about the diagnosis, so the typical appearance of the sores is key to the diagnosis. This appearance helps distinguish oral herpes from oral thrush, shingles, gonorrhea, and syphilis. In addition, chapped or sunburned lips can resemble oral herpes, but the tissue stain (Tzanck smear, see below) shows no virus-induced cell changes. Further testing is usually not necessary but is sometimes done.