Transcript: Herpes is one of the most common STDs out there, and once you’ve got it, you’ve got it for life. Yet outbreaks occur only occasionally, so what causes them?  Once genital herpes is contracted it lives in the body forever—often lying dormant—but it can become activated by certain triggers. While everyone’s triggers vary, there are some common experiences that make herpes flare-up in many people.  For example, some find that the friction of sex irritates the genital skin and brings on symptoms.  Using a water-based lubricant can help reduce this irritation, but DON’T use one that contains the spermacide nonoxynol-9.  This ingredient can irritate mucous membranes, such as the lining of the vagina, making symptoms worse. In addition, some people find that hormonal changes, such as those that occur during the menstrual cycle, can trigger outbreaks.  And one of the most universal causes of herpes flare-ups is a weakened immune system, like in people suffering from colds. Regardless of your personal triggers, herpes outbreaks can usually be tempered with medication and lifestyle changes, so talk to your doctor about your options!