Facial herpes is spread by a person infected with the herpes virus and somebody who was previously uninfected. Infection with HSV-1 is most commonly acquired during infancy or childhood as a result of contact with relatives (for example kissing). The source does not always have typical facial herpes symptoms at the time of transmission. For instance, the herpes virus is often shed from the lips before blisters appear and it is also possible to shed infectious herpes virus particles without noticeable symptoms.

Most people will have come into contact with the herpes virus between the ages of three and five but only one in three of these will have a first herpes episode with symptoms.

HSV invades the cells of the epidermis, the outer layer of the skin, causing fluid-filled blisters to appear. The herpes 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 herpes triggers include a fever (for example, a common cold), UV radiation (exposure to sunlight), extreme tiredness or lowered immune function.

The initial herpes 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 herpes 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 cold 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 directly to the site, to ease the discomfort of the cold sores so that they can eat and drink.

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

Recurrences

The herpes 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 further herpes outbreaks while others have regular recurrences. They seem to become less frequent with age.

A facial herpes outbreak has four stages:

1. A tingling feeling in the skin
2. Slight swelling and the development of a number of fluid-filled blisters, which are often painful
3. The blisters burst and form clusters, leaving fluid-filled sores (cold sores)
4. The cold sores eventually dry, scab over and heal without scarring after 8 to 10 days

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

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

The factors which can trigger herpes outbreaks differ from person to person. Menstruation, 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 a reappearance of cold sores in some people. In others, there is no definite cause.

People who experience an episode of herpes, either facial or genital, should consider themselves infectious from the start of the herpes episode to the healing of the last ulcer. During this time the herpes 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 of us acquire facial herpes in the first five years of our lives.

To help prevent herpes 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.

Hygiene is important for people infected with the herpes virus. Try to avoid direct contact with the cold sores but if this does occur, wash your hands with soap and water and dry thoroughly. Avoid picking at the cold 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 of cold sores in some cases.

Accurate diagnosis of facial herpes is made most easily and accurately at the time of an active herpes infection. A combination of the patient'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.

Possible complications

The cold 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, for example, has weakened the body's defences.

Treatment

Facial herpes may be treated, and sometimes even prevented, with an antiviral drug, valaciclovir, which is available as tablets (you need a doctor's prescription). There are also over-the-counter cold sore treatments your pharmacist can advise you about. Painkillers and a pain relieving mouthwash may also ease the symptoms. The treatment should be started as soon as the first symptoms appear. Each herpes episode can be treated with tablets or cream to speed the healing process. If episodes are very frequent or problematic, taking antiviral tablets daily may help prevent outbreaks.