Cold Sores

Cold sores are small groups of tender and painful blisters that appear on red swollen areas of skin, that usually heal without scarring. They are common, typically appearing on the lips and caused by the herpes simplex virus type 1 (HSV-1).. . The virus can only be transmitted by close personal contact such as kissing, and it is usually when the body's defences are weakened - due to flu, for example – that the virus is activated. Other triggers include menstruation, stress, fatigue, sunlight and cold winds. Cold sores cannot be caught from flannels, cups or towels.

What are the symptoms?

People react to the HSV-1 virus in different ways. Some people only have very mild symptoms or none at all, others have an unpleasant tingling feeling in the skin or lips that appear normal but there may be localized redness and swelling which is seen in response to the virus multiplying in the skin cells. Small blisters then appear that often seem to join together within a few hours at the site of redness or inflammation. Some of these blisters may look like small red bumps and are very tender. The blisters break and a moist sore can then appear - this is the most painful stage – before a crust or scab forms over the sore. These scabs usually become dry and eventually fall off although the area may stay slightly red for a couple of weeks as the skin finishes healing.  The virus can spread until the sores are completely covered by scabs. Around 20%  of people with HSV antibodies have recurrent attacks of cold sores throughout their lives and in children the virus can infect the mouth and throat, accompanied by fever and general aches and pains

Do I need any tests?

Tests are not usually needed to confirm the diagnosis of cold sores. Symptoms of tingling pain followed by the typical blisters that crust around the nose and mouth are usually enough to make the diagnosis.

Can cold sores be passed on to other people?

Yes. When you have a cold sore you should not kiss anyone or allow anyone to come into skin contact with the sore. In particular, avoid kissing newborn babies and anyone who has a poor immune system (immunocompromised). Immunocompromised people include people having chemotherapy for cancer and people with conditions such as AIDS. Avoid oral sex until the cold sores have completely healed.. Always avoid direct contact with the sores, so wash your hands after touching your lips. Never pick at the sores as this can spread the virus to other parts of the body or result in a bacterial infection of the sores. To strengthen your immune system, eat a varied diet, exercise regularly and get enough sleep. In some people, exposure to sunlight can cause a flare-up so using a sunblock may help. When you have no symptoms (when the virus is dormant), you are not usually infectious.

There is a risk of infecting the eyes with the cold sore virus if your contact lenses become contaminated. You can prevent this by carefully washing your hands before handling your contact lenses. If you have disposable lenses and you suspect you have contaminated them, it is best to throw them away. If you have any concerns it may be better to wear your glasses and seek advice from your GP or optometrist.

What is the usual treatment for cold sores?

Treatment is usually with aciclovir 5% cream, applied to the cold sore five times a day for five days. This can be bought over-the-counter from a pharmacy or prescribed by a doctor, and should be started as soon as the first symptoms appear. It can often reduce the length of the outbreak and the infectious period. Recurrences seem to become less frequent with age although complications are possible. Complications include infection with bacteria, damaged vision if the eyes are affected and, on occasion, spread to larger parts of the body. There are also other forms of over-the-counter treatment, with products that create a barrier around the infection to aid healing.