Cold Sores (herpes labialis)

The virus is an opportunistic invader, taking advantage of a depressed immune responses in a patient who is under psychological or physical distress. They are called "cold sores" or "fever blisters" because they tend to happen when the patient is physically burdened with another viral infection such as the cold virus. The image above is unusual because it was taken before the blister actually broke. All cold sores start as blisters, but the blister rarely survives for long enough to actually get a picture of it.

The image above is a more typical presentation of recurrent herpes simplex (a cold sore).

The herpes virus remains inactive in a branch of the local nerve trunk throughout life. Whenever the patient's immune system is depressed due to physical or psychological stresses, disease states, or even a common cold, the virus erupts into activity. This can happen numerous times throughout the patient's life, which is why cold sores are often called "Recurrent" herpes simplex. The above image shows a severe outbreak. During these outbreaks, the patient may also suffer numerous generalized flu-like symptoms such as fever, malaise, headache and body aches. This virus responds quite well to acyclovir or other anti-herpetic antibiotics.

The images above show an acute pair of herpes blisters that have coalesced to form one large lesion. the image on the right shows what it looks like 7 days later when healing is almost complete

The image below shows a case of primary herpes stomatitis in a child. The first herpes infection in a person of any age can be quite aggressive and cover quite a bit of the skin around the mouth as well as any of the tissues in the mouth. After the primary infection, which generally disappears without treatment in about two weeks, the virus "hides out" in the trigeminal nerves and manifests as a cold sore when the patient's immune system is at a low ebb such as when he or she is sick or under a lot of stress.

Herpes can also be transferred from the mouth to other parts of the body simply by touching the blister with the fingers and then touching other areas. When the virus is transfered to the eye, ocular herpes may result. Occular herpes can be very painful and dangerous. When a herpes blister forms on the fingers or the hand, the lesion is called a herpes whitlow (pictured above).

A Note on Genital Herpes

Herpes Simplex type I (HSV-1) prefers to infect the face and oral cavity. It is the virus most responsible for traditional cold sores and primary herpes stomatitis. There is, however a second variety of Herpes that prefers to infect the genital areas. Herpes Simplex Type II (HSV-2) is called "genital Herpes" because of its venereal (sexually transmitted) qualities. Both varieties produce similar lesions, the difference between them being their site specific preferences. Both establish latency (take up permanent residence) in nerve roots and once established, tend to cause occasional outbreaks with active lesions (sores) in areas of the body serviced by that particular nerve root. HSV-1 prefers to live in the trigeminal nerve root where it causes lesions in the oral cavity and on the face. HSV-2 takes up residence in the sacral ganglion at the base of the spine where it may cause genital lesions (see the dermatome chart on the Herpes zoster page).

Even though each type has site specific preferences, the viruses are genetically similar and can take up residence in nerve roots in other parts of the body, including in each other's territory. Outside of their own home territories, however, neither virus is especially virulent, and rarely cause recurrent outbreaks.

HSV-2 causes approximately 90% of all cases of genital herpes. Genital herpes caused by HSV-1 is generally much milder than that caused by HSV-2. HSV-1 is usually transferred to the genital area by direct oral/genital contact, although the virus is present in the saliva of infected individuals. Thus the use of saliva as a lubricant can, in fact, transfer HSV-1 to the genital area. HSV-1 is found in only about 10% of all cases of genital herpes, however most people infected with HSV-1 in the genital area have few, if any, outbreaks after the initial episode. HSV-2 prefers to live in this area and causes a much more virulent infection there.

On the other hand, HSV-1 causes almost all cases of oral and facial herpes. Oral herpes caused by HSV-2 almost never reoccurs, except in immunocompromised patients.

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