Herpes of the mouth is a viral infection. The virus HSV-1 may be transmitted by droplet spread – direct contact with saliva or even respiratory droplets. These droplets must make contact with broken skin or the mucous membranes in order to infect a person. The method of spread can involve kissing an infected person or even through touch. It can also be spread through the use of contaminated kitchen utensils. Sexual contact accounts for a small number of cases of HSV-1. Nevertheless it is a consideration when genital lesions are present. HSV-2 on the other hand is usually transmitted through sexual contact.
Human herpes virus 8 (HHV8) was recently discovered in the tumours called Kaposi's Sarcoma (KS). These tumours are found in people with AIDS and are otherwise very rare. KS forms purplish tumours in the skin and other tissues of some people with AIDS. It is very difficult to treat with medication. HHV8 may also cause other cancers, including certain lymphomas (lymph node cancers) associated with AIDS. The fact that these cancers are caused by a virus may explain why they tend to occur in people with AIDS when their immune systems begin to fail. The discovery also provides new hope that specific treatments for these tumours will be developed that target the virus.
Many HSV-infected people experience recurrence within the first year of infection. Prodrome precedes development of lesions. Prodromal symptoms include tingling (paresthesia), itching, and pain where lumbosacral nerves innervate the skin. Prodrome may occur as long as several days or as short as a few hours before lesions develop. Beginning antiviral treatment when prodrome is experienced can reduce the appearance and duration of lesions in some individuals. During recurrence, fewer lesions are likely to develop and are less painful and heal faster (within 5–10 days without antiviral treatment) than those occurring during the primary infection. Subsequent outbreaks tend to be periodic or episodic, occurring on average four or five times a year when not using antiviral therapy.
Avoid physical contact with anyone who has visible blisters and sores, and don't share towels or anything that may have come into contact with the sores. "It is also important that before you have any intimate contact with anyone you ask them about their sexual health, whether they have a herpes infection or have ever had any other sexually transmitted infection," Michael advises. "This is because statistically, people who have had an STI are more likely to be infected with the herpes virus. Using condoms and dental dams can also help reduce your risk of catching oral herpes."
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.