AskID: Cold sores

We asked Prof Caitriona Ryan:
‘Recurrent cold sores (herpes simplex labialis) is a very common and bothersome condition caused by herpes simplex virus. Approximately 2/3 of adults carry this virus. It typically affects the lips and areas around the mouth but can also affect the nose, cheeks and other parts of the face. It is rarely serious but if the outbreak spreads to the eyes, damage to the cornea can result and medical assistance should be sought immediately.

After an initial outbreak, the virus stays dormant inside the nerve cells which supply sensation to the skin. After the primary episode of infection, During a recurrence, the virus follows the nerves onto the skin, where it multiplies, causing the cold sore. After each attack and lifelong, it enters the resting state. Reactivation can happen at any time but certain triggers can make an outbreak more likely, such as virus such as fever, menstruation, a high-stress event, fatigue, a weakened immune system, a cold or infection, sunburn, dental work, surgery, laser or filler injections. Tingling or warmth on or near the lips is usually a warning sign that the cold sores of recurrent oral herpes are about to appear in 1 to 2 days.

When an outbreak occurs, pain relief with paracetomol can help. Several anti-viral over the counter topical preparations are available but these creams usually only shorten an oral herpes relapse by 1 or 2 days. Starting an oral antiviral medication such as valciclovir, acyclovir or famciclovir can abort or significantly reduce the severity of an outbreak but these medications work better if you take them as soon as you experience the first signs of a mouth sore, such as tingling of the lips, before the blisters appear.

In those that experience very frequent outbreaks, treatment with a daily oral antiviral medication can help to prevent outbreaks. Similarly, patients who are prone to cold sores should take prophylactic anti-viral treatment when undergoing dental surgery, laser treatment or before lip fillers. Use of SPF on the lips can also help reduce UV- induced breakouts.’