Can cold weather trigger cold sores?

Cold sores can happen at any time of year, but many people find that they can be especially troublesome in the colder months.

What are cold sores?

"Cold sores are small blisters that develop around the lips or mouth, caused by the herpes simplex virus (HSV)," says Dr Anjali Mahto, consultant dermatologist and spokesperson for The British Skin Foundation.

"They usually resolve without treatment in seven to ten days. The blisters can often be preceded by tingling, itching or burning in the affected area."

The majority of people will be infected by one of the viruses which cause cold sores (HSV-1 and HSV-2) at some point. Some people never get any symptoms or only have one cold sore outbreak ever. Others may experience recurrent outbreaks with various triggers.

Whilst cold sores are self-limiting, meaning that they heal on their own, they can be painful and uncomfortable, particularly if you get frequent outbreaks. There are things you can do to speed up healing and reduce any discomfort but, where possible, prevention is better than a cure. So which triggers should you look out for and avoid in the winter period?

Winter weather

Cold weather itself may be to blame for your winter cold sore outbreak. "Cold weather may possibly reactivate the cold sore virus," says Mahto. "Changes in temperature such as going from cold outdoor weather to warm indoor homes may be causative."

The colder weather and stark changes in temperature affect the skin, particularly if it's windy or bitter. "Lips are likely to be dry and chapped in the winter. This can result in problems with barrier function and make conditions suitable for HSV to replicate," she says.

Simply going from the frosty outdoors into a heated home is traumatic enough for the skin to be provided with the perfect environment for the cold sore virus to flare up.

"The cold sore virus lies dormant a long way away from the lips, in the nerve ganglia up behind the cheekbone. But it is sensitive to changes in the environment of the other, superficial end of nerve," explains specialty doctor and medical journalist Dr Patricia Macnair.

"Both cold weather and central heating can dry out the surface of the lips. The nerve endings in the skin are affected by this change, triggering the virus to start replicating again, and travel down the nerve to break out on the skin. Some have suggested that this is a self-preservation mechanism for the virus - it senses things changing in its host (the human) and so makes a bolt for the skin and a way out to find a new healthier host."

Use lip balm throughout the winter to prevent your lips drying out and avoid damage to the skin. Try to protect your lips behind a scarf when there are harsh winter winds, to prevent them becoming chapped in the first place. Make sure not to share your lip balm with other people so as to not catch or pass on HSV or other infections.

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Immune system and illness

The immune system often takes a bit of a battering in the winter months. With fewer daylight hours, we don't take in as much vitamin D and we might not be getting out to do exercise whilst it's cold and dark. Our diets might also move away from summery salads towards carb-heavy comfort food in the winter months which means we might not be getting all of the nutrients we need on a daily basis.

With a depleted immune system, the body is more susceptible to illness, including the common cold, and thus cold sores, says Mahto.

"Increased frequency of upper respiratory tract infections like the common cold virus causes a reactivation of the herpes simplex virus on the skin."

Having a cold and being generally unwell or run-down all increase your risk of a cold sore developing. "Reducing the risk of upper respiratory tract infections may help to prevent flares of cold sores," she explains.

The body can't fight off other infections as easily when the immune system is weakened or fighting off other illnesses.

"Again, the virus remains latent in the nerve ganglion, probably held in check partly by a healthy immune system," says Macnair. "But anything that weakens the host's immune control allows the virus to start reproducing and jump into action again. It's the same theory - if the host's immune system is failing or illness is taking over, the virus needs to get out and find a new host."

Take precautions during the winter months to prevent yourself catching the common cold, coughs, sore throats and the flu. This in turn may prevent you developing a cold sore outbreak, as well as keeping you feeling well.

"Physical interventions such as frequent hand washing and use of alcohol hand disinfectants, zinc supplements and probiotics have in some studies shown a possible beneficial effect in reducing the risk of developing upper respiratory tract infections," says Mahto.

Stress

"Stress during the holiday period may be a contributor," says Mahto.

As fun as the festive season can be, we all know that it can cause you to feel stressed, whether because of preparations for Christmas, being cooped up inside with the kids or work pressure in the final push towards the New Year.

Not only does stress contribute to cold sore outbreaks, but the longer that you feel stressed, the more likely it is that you will develop a cold sore. Stress also impacts your sleep and immune system, contributing to you feeling run-down.

Try to avoid becoming run down and exhausted at the end of the year by resting, exercising and practising mindfulness or other stress-relieving techniques.

Winter tanning

If you're someone who likes to have a tan, you might be planning to head to a salon to 'top up' your summer glow over the darker Christmas period.

Exposing your skin to the sun and using tanning beds is never a good idea as it significantly raises your risk of developing skin cancer. But not only is it dangerous, it could also trigger a cold sore outbreak as UV light damages the immune system.

This applies to any exposure to the sun or other forms of UV light throughout the year. It's important to protect your skin, including your lips, using SPF and reapplying regularly whether you're heading to a hot country or somewhere snowy (as snow reflects UV).

"These can all change the host's immune system or the local environment around the nerve ending, which triggers the virus back into action," says Macnair.

Unless you never leave your house, exposure to temperature changes, sunlight and various winter illnesses is pretty much unavoidable. But reducing your risk and being aware of your triggers will go a long way in preventing cold sores. And if all else fails, make sure to start treating your outbreak as soon as possible to minimise your symptoms and speed up healing!