Cold sores are painful, fluid-filled, blister-like lesions that appear on or surrounding the lips. Cold sores are caused by the contagious viral organism, herpes simplex virus, or HSV. Two types of herpes exist: Type 1 and Type 2. Cold sores are mostly associated with Type 1 infections. According to the Mayo Clinic health library, the recurrence of a herpes outbreak can be triggered by a compromising time in a person’s life. Situations that cause the immune system to be lowered or suppressed can cause the herpes virus to come out of its latent or dormant phase.
Stress
Stress is a factor in depressed immune system function. The stress hormone cortisol directly affects immunity by suppressing at least one aspect of the innate immune response, namely inflammation. Natural cortisone and its synthetic derivatives, corticosteroids are used to suppress inflammation of disease. A 2001 Medical Hypothesis journal article concluded that the release of various chemicals during periods of both acute and chronic stress is at the root of immune system compromise in herpes sufferers. The diminished immune response can trigger viral reactivation and a new outbreak.
Fever and Illness
During an acute illness such as the cold or flu, the body is using its full immune system armament; from the microbe-engulfing cells, otherwise known as macrophages, to the production of antibodies, cytototoxic and natural killer cells. The defense system is fully engaged in an attempt to trap and kill the microbes causing the acute attack and acquire the nutrients to heal the damage caused by these organisms. All the while, the latent or hidden herpes virus that has been kept quite by the surveillance of an alert and fully functioning immune system is temporarily neglected.
While off guard from the immune system, the herpes virus comes out of its sleeping phase, inducing the symptoms of itching or burning at the site where the blister-like lesion will develop. Within 24 to 48 hours a full-blown cold sore outbreak is in effect, notes the Mayo Clinic health library. The appearance of cold sores during the time of a fever or illness has provided the background for the other commonly used name for cold sores, fever blisters.
Sunlight
It appears that immunosuppression is also at the root of recurrent cold sore outbreaks, according to a 1994 Cutis journal article that measured HSV-1 cold sore outbreaks during the summer months. In the very large study population of 3,678 patients, roughly 10 percent were classified as having sun-induced flare-ups. However, as the heat of the summer sun increased throughout the months of June, July and August, the sunlight-induced flare-ups increased from 19.7, to 28 and finally 40 percent, respectively. The article concluded that solar UV exposure could induce recurrent cold sores secondary to either a lowered immune system or the direct reactivation of the dormant virus.
