  
|  |
|
|
|
Reviewed by Dr John Pillinger, GP
|
What are cold sores?
Cold sores are a very common illness caused by the herpes
simplex virus (HSV).
The disorder is characterised by groups of fluid-filled blisters
which appear on red swollen areas of the skin or on the mucous membranes. The
areas can be tender and painful. The blisters heal without scarring but have a
tendency to recur.
-
There are two types of herpes simplex
virus.
-
HSV-1, which is the most common type, usually causes cold sores
(oral herpes). HSV-2 usually causes genital herpes. But both types can infect
any area of the skin or mucous membranes.
-
Approximately 80 per cent of the adult population have
antibodies against HSV-1 in their blood.
-
Around 25 per cent of the adult population have antibodies
against HSV-2.
What causes the virus?
The virus can only be transmitted by close personal contact such
as kissing. Most people will have come into contact with the virus between the
ages of three and five but will not show any symptoms until after
puberty.
HSV invades the cells of the epidermis, the outer layer of the
skin, causing fluid-filled blisters to appear. The virus travels from the
epidermis along the nerve paths to the roots of the nerves where it becomes
inactive.
A weakening of the body's defences, due to a severe
cold for example, can
lead to a reactivation of the virus and a return of the blisters.
What are the symptoms?
The primary infection can progress in different ways. Some
people only have very mild symptoms or none at all. The first outbreak starts
one to three weeks after the virus has been contracted. It subsides
spontaneously within a few weeks. Later, if HSV is reactivated, the blisters
will return.
The first symptom of an outbreak is an unpleasant tingling
feeling in the skin. After a short while, a number of fluid-filled blisters
appear.
The sores become covered by scabs that, typically, fall off
after 8 to 10 days. The virus can spread until the sores are completely covered
by scabs.
Around 20 per cent of the people with HSV antibodies have
recurrent attacks of cold sores throughout their lives.
In children, the virus can infect the mouth and throat. The
infection may be accompanied by a fever and general aches and
pains.
What can be done to prevent cold sores?
-
Avoid direct contact with the sores. These can appear on every
part of the body, including the fingers and genitals.
-
Wash your hands after touching the lips.
-
Avoid picking at the sores as this can spread the virus to
other parts of the body or result in a bacterial infection of the
sores.
-
The body's defences can be strengthened by a healthy
lifestyle. Eat a varied diet, exercise regularly and get enough
sleep.
-
The factors which trigger outbreaks differ from person to
person.
-
Menstruation, fever
and exposure to sunlight can cause a reactivation in some people. In others,
there is no demonstrable cause. Using a sunblock may help to prevent a
reactivation.
How are cold sores diagnosed?
A combination of the patient's medical history and the
appearance of the sores will usually be sufficient for a diagnosis. A scrape or
a
blood sample can be
used to confirm it.
Possible complications
-
The sores may become infected by bacteria.
-
If the condition spreads to the eyes, it can damage
vision.
-
In patients who suffer from
atopic dermatitis,
the cold sores can, in rare cases, spread to larger parts of the
body.
-
Massive cold sores can be a sign that another disease,
pneumonia or HIV for
example, has weakened the body's defences.
How are cold sores treated?
Treatment is
aciclovir 5 per cent
cream (eg Zovirax cold sore cream), applied to the cold sore five times a day for five days. This can
be bought over-the-counter from a pharmacy or obtained on
prescription.
The treatment should be started as soon as the first symptoms
appear. It can often reduce the length of the outbreak and the infectious
period.
Recurrent severe attacks can be treated by
anti-HSV agents in
pill form.
Future prospects
The development of the disease differs from person to person.
Some people will have few or no reactivations while others have recurrent
outbreaks. Recurrences seem to become less frequent with age.
|
Based on a text by Dr Flemming Andersen
|
Last updated 01.05.2005
|
 |
|
|
 |
| |      |
|
