What are cold sores and fever blisters?

Both names, cold sore and fever blister, refer to the lip blisters caused by infections of the herpes simplex virus. These infections are associated with Herpes Simplex I (not to be confused with Herpes Simplex II, which is generally associated with genital herpes). Cold Sores are viral infections which cause recurrent groups of irritating, even painful blisters on the lips.

This virus affects more than half of the adult population, and over 50 million people in the US experience at least one cold sore outbreak per year. It is second only to the common cold in prevalence. Once a person contracts the virus, it may exist in a latent or dormant state throughout his or her lifetime. After a cold sore first appears, it has a tendency to recur frequently in the same spot.

A cold sore sufferer usually feels a sensation of heat, tingling, irritation or itching about 24 hours before a blister appears. The fluid filled blister frequently breaks in the first few days, while total healing usually takes 4-10 days.

Cold sores are contagious, so care should be taken to avoid contact with this area. Touching the infected area may result in infection elsewhere, and the virus can be passed to others.

These blisters have become known as cold sores or fever blisters since they can develop when a person has a cold or fever. But outbreaks frequently follow sun exposure, trauma, examination stress, emotional discomfort, the start of menstruation or intestinal upset--occasionally, they have no obvious cause at all.

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