What triggers cold sore (fever blister) breakouts?
Cold sores form when the herpes virus gets reactivated.
After a person's initial herpes simplex virus infection (either subclinical or full-blown) some of the herpes virus particles (virions) will remain in the person's system, and remain there forever.
Most of the time, these virions will lie dormant in the person's system and cause no overt effects. At times, however, they can become active. And when this reactivation occurs the person will experience the outbreak of a cold sore.
What causes the the reactivation of the herpes virus?
What triggers cold sore outbreaks?
Each of the following has been found to be an event that, for many, appears to be closely associated with the formation of their cold sores.
- Emotional upset and stress.
- Physical stress and fatigue.
- Illnesses (including a cold or the flu).
- Injury to the lips or skin, such as physical trauma or severe chapping.
- Injury to the lips from excessive exposure to bright sunlight or ultraviolet lamps.
- Menstruation or pregnancy.
- An immune system deficiency.
Get the upper hand on managing cold sores by learning when to expect them.
Research has shown that today's antiviral medications for cold sores can significantly minimize outbreak severity and duration if their use is started early enough. This "early" treatment approach is typically also encouraged with OTC products and home remedy treatments.
By observing which factors typically trigger their cold sores a person can learn when to anticipate an outbreak. If a person begins the use of medications early enough (preferably during the Tingle stage) they can quite possibly reduce their cold sore symptoms dramatically.
The timing of fever blister outbreaks is often associated immune system stress.
Several of the factors listed above seem to correlate with those time periods when a person's immune system typically would be weakened or stressed. When compromised, a person's immune system, which under normal circumstances would be able to keep the herpes virus particles in check, can be overwhelmed and therefore a window of opportunity for cold sore formation opened.
Where do the dormant herpes virions that cause cold sores reside?
As we mentioned previously, it is the reactivation of dormant herpes simplex virions that is the cause of cold sores.
Between outbreak episodes, the dormant virus particles lie quietly "asleep" in nerve tissue. (In the case of HSV1 these dormant virions usually reside in the trigeminal nerve ganglion.) Once reactivated the virus travels down the nerve to the area of the face where the cold sore lesion ultimately forms. (If you're interested, here are some pictures of herpes simplex virions.)
In most cases a person's cold sores will always recur in essentially the same general area. This is because this is the region that is serviced by the nerve that harbors the dormant virus.
How common is it that a person has been exposed to the herpes simplex virus (HSV1)?
It has been estimated that up to 80% of the general population has the presence of herpes simplex virus antibodies in their blood. Antibodies are proof positive that a person has been exposed because our immune system only creates them in response to the physical presence of virions within our bodies.
The good news is, at least from a statistical standpoint, that although about 80% of the general population has been infected with the herpes simplex virus (HSV1) it's in only about one third of these people that the residual virus particles will become active at times and cause recurrent outbreaks of cold sores (fever blisters). The rest of us do still carry the virus but, for whatever reasons, it remains dormant and we remain cold-sore free.
