What are cold sores (facial herpes)?

Cold sores (facial herpes) are fluid-filled blisters that appear on the skin (often affecting the lips) or mucous membranes and are often preceded by pain and tingling. Cold sores are caused by infection with the herpes simplex virus (HSV). Facial herpes is spread by close physical contact with an infected person and is commonly acquired during infancy or childhood. Facial herpes is very common and is also known as fever blisters, sun blisters, oro-facial herpes, herpes labialis and herpes febrilis.

Symptoms of cold sores

Facial herpes is characterised by groups of fluid-filled blisters that appear on red swollen areas of the skin or mucous membranes. A burning sensation is often present just before the skin lesions develop. The areas can be tender and painful. The blisters heal without scarring but have a tendency to return.

Two types of HSV

There are two types of herpes simplex virus (HSV):

• HSV-1, the most common type, which usually causes facial herpes.
• HSV-2, which usually causes genital herpes.

Although cross-infection can occur, it is more common from the face-to-genitals route (causing genital HSV-1) than from the genitals to the facial area.

Nearly 50% of genital herpes is caused by HSV-1 (the cold sore type virus), through oral to genital contact.

How do you catch facial herpes?

Facial herpes is spread by close physical contact between an infected person and somebody who was previously not infected. The source does not always have typical facial herpes symptoms at the time of transmission. For instance, the virus is often shed from the lips before blisters appear and it is also possible to shed infectious virus particles without noticeable symptoms.

Most people will have come into contact with the virus between the ages of three and five (for example, through being kissed or hugged by a relative who has the virus), but only one in three of these will have a first episode with symptoms.

What does the virus do?

The 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 trigeminal ganglion, a bundle of nerves close to the inner ear, where it lies hidden until it is reactivated.

Potential triggers include a fever (eg, a common cold), UV radiation (exposure to sunlight), extreme tiredness or lowered immune function.

The initial infection

When a person is infected with herpes for the first time, the episode is called a primary infection. The primary infection can progress in different ways. Some people only have very mild symptoms or none at all but others can experience considerable discomfort. Sores can develop inside the mouth, as well as outside it, and this is commonly called gingivostomatitis.

Initially, this can take the form of painful sores affecting the mouth, gum, throat and lips, which may last for more than 14 days if left untreated. Gingivostomatitis should be treated with antiviral medicine. Most patients also require painkillers or even local anaesthetics, applied direct to the site, to ease the discomfort so they can eat and drink.

This first outbreak starts one to three weeks after the virus has invaded the skin and subsides within a few weeks.

Recurrences

The virus remains hidden in the nerves for the rest of the person's life and becomes active again from time to time. Some people have few or no outbreaks while others have regular recurrences. They seem to become less frequent with age.

An outbreak has four stages:

• a tingling feeling in the skin
• slight swelling and then development of a number of fluid-filled blisters, which are often painful
• the blisters burst and form clusters, leaving fluid-filled sores
• the sores eventually dry, scab over and heal without scarring after 8 to 10 days.

The virus can spread until the sores are completely covered by scabs and the infection will usually be external.

Sites of infection

Most commonly, herpes simplex affects the lips or nasal region, causing cold sores. Recurrences may affect the eye region or even involve the eye itself. Eye infection with HSV is also known by several other names, including: herpes keratitis, herpes conjunctivitis and herpes stromal keratitis. Deep infection of the eye is very rare, but can cause a syndrome called acute retinal necrosis.

In children, the virus can infect the mouth and throat. The infection may be accompanied by a fever and general aches and pains.

Also see the topic on Herpes virus and pregnancy

What triggers facial herpes?

The factors which can trigger outbreaks differ from person to person. Menstruation (periods), trauma, fever, exposure to sunlight, extreme weather conditions or anything that lowers the immune system, such as a cold, flu or general illness, can cause reappearance in some people. In others, there is no definite cause.

Transmitting facial herpes

People who experience an episode of herpes, either facial or genital, should consider themselves infectious from the start of the episode to the healing of the last ulcer. During this time the virus can be transmitted to other people and, in rare cases, can be transferred to other areas of the body.

Increasingly, genital herpes (genital HSV-1) is being caused by face-to-genital transmission. Remember, most people acquire facial herpes in the first five years of life.

To help prevent transmission, you should AVOID:

• kissing anyone or sharing drinking utensils when you have a cold sore present.
• having oral sex when you or your partner have facial or genital sores.
• sharing towels and face flannels.
• using saliva to wet contact lenses if you have sores around your mouth.

Precautions - hygiene is important

Hygiene is important for people infected with this virus. Try to avoid direct contact with the sores but, if this does occur, wash your hands with soap and water, and dry them thoroughly. 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. Avoid the use of harsh detergents on the skin.

The body's defences can be strengthened by a healthy lifestyle. Try to eat a varied diet, exercise regularly and get enough sleep. Using a sunblock may help to prevent a recurrence in some cases.

How to diagnose facial herpes

Accurate diagnosis of facial herpes is made most easily and accurately at the time of an active herpes infection. A combination of the person's medical history and the appearance of the sores will usually be sufficient to identify facial herpes. A swab of the lesion or a specialised blood test can be used to confirm it.

*Also see our other topic – ‘Herpes simplex’ which includes photos of lesions

Possible complications

The sores may become infected by bacteria. If the condition spreads to the eyes, in severe cases, it can damage vision. In patients who suffer from atopic dermatitis, in rare cases, the cold sores can spread to larger parts of the body.

Massive cold sores can be a sign that another disease, pneumonia or HIV (human immunodeficiency virus), for example, has weakened the body's defences.

Treatment

Facial herpes may be treated, and sometimes even prevented, with an antiviral medicine. Painkillers and a pain-relieving mouthwash may also ease the symptoms. The treatment should be started as soon as the first symptoms appear (such as tingling). Each episode can be treated to speed the healing process.

More information on over-the-counter cold sore (facial herpes) treatments.

If episodes are very frequent or problematic, taking antiviral tablets daily may help prevent outbreaks – see your GP or doctor at your local sexual health clinic if recurrences are a problem.

Original material provided by the New Zealand Herpes Foundation. Edited by everybody, August 2010.