In order to diagnose herpes, a health care provider can swab an area of visibly active herpes infection or, if symptoms aren’t active, a blood test can be given that measures the number of herpes antibodies present in the body. The antibodies don’t indicate herpes itself, but rather show the immune system’s response to the presence of the virus in the body. It’s important to note that sometimes a swab can give false negative results since herpes lesions need to be large enough to yield enough detectable virus and if the outbreak is already healing it also may not be detected in a swab. (6)
Herpes infection can cause sores or breaks in the skin or lining of the mouth, vagina, and rectum. This provides a way for HIV to enter the body. Even without visible sores, having genital herpes increases the number of CD4 cells (the cells that HIV targets for entry into the body) found in the lining of the genitals. When a person has both HIV and genital herpes, the chances are higher that HIV will be spread to an HIV-uninfected sex partner during sexual contact with their partner’s mouth, vagina, or rectum.
Recurrent outbreaks of genital herpes may happen, with some patients having four to six outbreaks in the span of a year. Compared to the first infection, subsequent recurrences are less painful and occur in shorter periods than the first infection. There are some patients, however, who don’t have another outbreak for many years or even once more during their lifetime.11
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.