cold sores / fever blisters / oral herpes

Cold sores, also frequently referred to as "fever blisters", are painful and unsightly mouth sores that are caused by an outbreak of the herpes simplex virus. The following pages will help you understand what triggers cold sores and how to identify a mouth sore as being a cold sore.
     Also in our pages you will also find a discussion about the treatment of cold sores, including the use of home remedies and over-the-counter medications. At our discussion's end we describe the prescription cold sore medication penciclovir (trade name Denavir).

What are cold sores?

Cold sores are a type of facial sore that are found either on the lips or else on the skin in the area near the mouth. Some equivalent terminology used for cold sores is "fever blisters" and the medical term "recurrent herpes labialis".


Specifically what causes cold sores?

Cold sores are caused by the herpes simplex virus. No doubt you've heard of "herpes" before, but don't jump ahead of yourself. There are actually two types of herpes simplex virus, "type 1" and "type 2".

Type 1 herpes simplex virus.

Herpes simplex virus type 1 ("HSV1") generally only infects those body tissues that lie "above the waistline" and it is HSV1 that causes cold sores in the majority of cases.

Type 2 herpes simplex virus.

Herpes simplex virus type 2 ("HSV2") typically only infects those body tissues that lie "below the waistline" and it is this virus that is also known as "genital herpes". Herpes simplex virus type 2 is not usually the virus that causes cold sores, although it can.

How do people get exposed to the herpes simplex virus that causes their cold sores?

When you think of having an infection you usually assume that you were recently exposed to the germ which has caused your problem. With cold sores this is not the case. Cold sores are not a sign of a recently acquired herpes simplex infection but instead a reactivation of virus particles already living in your body. Cold sores occur when latent herpes simplex virus, which has been lying dormant ("asleep"), becomes reactivated.

 

Where does this dormant herpes simplex virus come from?

The dormant herpes virus particles come from a previous infection. A person's initial herpes simplex virus infection, termed "primary herpetic stomatitis", does not usually take the form of a cold sore and therefore a person may not relate their initial exposure to the herpes virus to the recurrent cold sores they get.

What are the signs and symptoms of a person's initial herpes (HSV1) infection?

The classic full-blown symptoms of a person's initial infection of the herpes simplex virus (termed "primary herpetic stomatitis") takes the following form:

• The first signs of the infection are characterized by nonspecific constitutional symptoms such as: fever, irritability, headache, and pain upon swallowing.
• A day or so after the infection's initial signs have appeared the person's mouth will become painful and their gums will be intensely inflamed.
• Usually by day three of the infection a number of tiny blisters have formed throughout the person's mouth.
• These blisters soon rupture resulting in gray colored ulcers.
• These ulcers can be very painful and often interfere with a person's ability to eat.
• The ulcers will eventually heal. Usually the entire infection has run its course within 10 to 14 days.

Click this link to see a photograph of primary herpetic stomatitis (primary herpes), provided by the Bristol Biomedical Image Archive. [A new browser window will be opened.]

Why don't the symptoms of primary herpetic stomatitis seem familiar to you?

If you don't remember having had the classic signs and symptoms of primary herpetic stomatitis it might be because you experienced them as a small child. Most cases occur before the age of 7.

Additionally, if you don't remember having all the classic signs and symptoms, it's probably because your case was subclinical. This is by far the most common occurrence. It has been estimated that 99% of all cases of primary herpetic stomatitis are subclinical, meaning that the course the infection ran was so slight that its symptoms were not apparent. It is quite possible that when you had the infection that, at most, you only experienced one or two mild mouth sores.

Cold Sores & Fever Blisters

• Page 1
  • What causes cold sores?
• Page 2
  • How common is the herpes virus?
  • What triggers cold sore break outs?
• Page 3
  • What are the characteristics of cold sores?
  • What are the stages of cold sore formation?
  • Are cold sores contagious?
• Page 4
  • Over-the-counter medications for cold sores.
  • Home remedies for cold sores.
• Page 5
  • Prescription medications for cold sores.