Cold sores: what are the causes, how do they appear and how to control them?

Cold sores, sometimes called fever blisters, are a common skin condition caused by the herpes simplex virus type 1 (HSV-1). Generally harmless, they are contagious, often painful, and tend to recur after the initial infection. This is because the virus remains in the body for life, “hiding” in nerve cells, and is reactivated by certain triggers.

What causes cold sores on the lips?

The main cause is HSV-1, often contracted during childhood through close contact, such as kissing or sharing objects. After the primary infection, the virus remains in the body and can remain dormant for a long time. HSV-1 is different from HSV-2, which is more often associated with genital rashes, but the two viruses can affect different areas depending on how they are transmitted from person to person.

What can cause an exacerbation?

Even when the virus is “dormant,” certain situations can activate it and cause a new epidemic:

• stress (mental or physical)

• illness (e.g., cold or fever)

• weakened immunity

• hormonal changes (e.g. during menstruation)

• sun exposure (especially on the lips)

• fatigue or lack of sleep

Rashes usually appear as painful sores around the mouth, nose, chin, or on the cheeks.