Herpes Simplex Virus
Herpes simplex viruses HSV-1 and HSV-2 cause outbreaks on the skin and mucous membranes, often referred to as “cold sores.” After the initial infection, the virus travels to a nerve cell and becomes dormant. When reactivated by ultraviolet light, emotional stress, surgery, trauma, or hormone level fluctuation, the virus reproduces and travels down the nerve to the skin, where it produces recurring infections.