When a person is infected with herpes for the first time, the episode is called a primary infection. Symptoms vary from none at all through to moderate discomfort. This first outbreak starts 1–3 weeks after the virus has invaded the skin and subsides within a few weeks.
An outbreak has 4 stages:
- A tingling feeling in the skin.
- Slight swelling and then development of a number of fluid-filled blisters, which are often painful.
- The blisters burst and form clusters, leaving fluid-filled sores.
- The sores eventually dry, scab over and heal without scarring after 8–10 days.
The virus can spread until the sores are completely covered by scabs. Once healed, the virus can still be shed (or passed onto someone else), but the risk is much lower.
Image credit: DermNet NZ
If sores develop inside the mouth, as well as outside, it's often called gingivostomatitis. This should be treated with antiviral medicine (eg, aciclovir or valaciclovir) and pain relief as sores and blisters lining the mouth and throat make it harder to eat and drink and take longer to heal – up to 14 days.
Herpes simplex can also cause infection in other places:
- Herpetic whitlow – small red blisters or tender lumps on fingers and hands.
- Scrum pox – facial blisters in a rugby player from direct contact.
- Infants may develop mouth sores when exposed.
Once you have been infected, the virus remains hidden in your nerves for the rest of your life and becomes active again from time to time. Triggers can include a fever, a common cold, UV radiation (exposure to sunlight), extreme tiredness or lowered immune function. Some people have regular outbreaks or recurrences, while others have none. With time, these become less frequent.