Weather you like it, weather you don’t

How does temperature affect your skin?

Our bodies react as seasons change and the temperature fluctuates. Our
skin, of course, is at the front line of personal climate change. What can
we do to combat the effects of winter cold or extreme heat, and is air-
conditioning the nemesis of dermatologists? Dr. George Moncrieff answers your questions.

Is cold weather bad for my skin?

It depends on your skin but all eczemas and dry skin conditions, including psoriasis, are aggravated by cold weather.
There are several factors at play. Firstly, when it’s cold, any moisture in the air condenses onto surfaces such as glass – your car windows, for example, on a winter morning.
That means the the air around you becomes drier and that, in turn, increases water loss from your skin. Dry skin becomes drier.
At the same time, at lower temperatures your body needs to stay warm by conserving heat loss, and it does that by reducing blood flow to the skin. It’s a natural protective mechanism but it has consequences for the skin because less blood limits production of the natural oils that support the skin barrier.

On top of that, in cold weather, we don’t sweat as much. We don’t need to. The problem is, sweat helps draw those precious natural oils to the surface. Sweat is also mildly acidic and its acidity helps maintain the ‘acid mantle’ that is so essential for skin health (see below for more details). So, without sweat, the acid mantle is weakened.

There are other factors, too. In cold weather, we tend to wear more clothes and often clothes made of wool because they’re warm. Perfectly sensible. But the fibers from wool often catch on rough areas of skin, such as those caused by eczema, and cause irritation.

Finally, we usually get less sunlight in colder weather, partly because we go out less and cover up more and partly because the days are shorter and the sunlight is weaker. That’s not ideal either, because sunlight generally helps eczema, psoriasis, and many other skin conditions.
Ultraviolet light therapy can be used to treat a number of these skin conditions and works partly through an immune-regulating effect of UV light and partly through stimulating the production of vitamin D in the skin.

Recent research has shown that most patients with moderate or severe atopic pattern eczema are vitamin D deficient, many severely. Correcting that with oral vitamin D supplements helps to control their eczema.
In winter months most people become significantly vitamin d deficient. Besides regulating calcium absorption and bone health, vitamin D has critical roles in our bodies which include immune modulation (fighting infections) and possibly cancer prevention. This is an even more serious problem for people of dark skin who are less able to produce vitamin d from sunlight.

We therefore recommend that everyone takes vitamin D supplementation especially during the winter months and especially those with skin diseases like eczema.

All in all, cold weather is not the skin’s best friend!
A number of conditions, some well-known, some less familiar, are associated with cold weather.

These include:
Chilblains (perniosis):
Most of us will have experienced chilblains on extremities such as toes and fingers, especially if the skin becomes wet for any length of time.

Cold-induced urticaria:
This is a relatively rare form of urticaria (wheals or hives) induced by exposure to cold.

Raynaud’s phenomenon:
If you’re prone to this painful condition you are likely to feel it in the fingers on cold days.

Some people with rosacea report that temperature changes, including exposure to cold air, can trigger a facial flush and aggravate their rosacea.

Should I change my skincare routine each season?

Yes, is the short answer. Changing your routine can help.
In winter it is even more critical to avoid harsh detergents and limit exposure to soaps, shower gels and shampoos. These all de-grease the skin – that’s how they work, and why we use them – which means those protective natural oils that help keep your skin healthy are removed.

But also, being alkaline, soaps destroy the protective acid mantle on the surface of your skin. The mantle is antibacterial and helps maintain the normal healthy skin microbiome while controlling the activity of enzymes that break the bonds holding skin cells together. You want to avoid damaging it.

If you have eczema or dry skin it is even more important in cold weather to wash with an emollient soap substitute, and to apply a quality leave-on emollient more frequently. Clothing choices might change, too. Avoiding wool should help. Cotton – or better still, silk – is easier on the skin.

Pay special attention to your hands because they are usually exposed to more washing and the cold.
You might want to use sunscreen in winter, too. The intensity of UV-A light is hardly affected by the season, nor indeed by the time of day or degree of cloud cover, and it penetrates glass.
It’s always there, and while UV-A doesn’t cause sunburn, it does go deep into the skin causing sun damage and aging effects, so a UV-A sunblock in winter is a great investment.

What about warmer weather?

In warm weather most dry skin conditions improve so you can probably be less vigilant regarding soap avoidance.
Sun protection is the biggest issue because, in warmer weather, you’re likely to be out and about more. A good quality sunblock is essential, and probably the most important step you can take to keep your skin healthy.

A little sun is no bad thing. UV-B light not only increases vitamin D levels, but also has anti-inflammatory benefits, which can be particularly helpful if you have eczema or psoriasis. (In fact UV light is used to treat many skin conditions.) But avoiding sunburn and skin damage is absolutely crucial, so always an SPF all year round but be especially vigilant about applying sunblock between the hours of 10am and 3pm when you’re outside on clear days between March and September.

How does central heating affect my skin?

Most forms of heating will dry the air and make dry skin conditions worse. Using a humidifier, having some house plants or placing a water source near a radiator will help to some extent.
Central heating is also the dust mites friend, and we know they can be troublesome for people with lung conditions such as asthma. Having said that, dust mites are not usually a problem for eczema.
Don’t turn the thermostat up too high, though. Becoming overheated can cause painful or itchy bumps in some people – a condition known as cholinergic urticaria.

What about air-conditioning?

Air-conditioning dramatically reduces humidity – the moisture in the air – and can really aggravate dry skin conditions. What can you do? Avoid air-conditioned environments as much as you can, simple as that.

Are freckles a cause for concern?

No. Freckles typically occur in people with fair skin, who burn easily, rarely tan, and are therefore at higher risk of developing skin cancers. They’re not dangerous in themselves but they are a marker of an ineffective response to sun exposure and potentially damaging amounts of lifetime UV exposure. Remember to use that sunscreen.

The only other possible problem with freckles is that a more sinister pigmented lesion such as an early melanoma could be ‘hidden’ by a large number of freckles. You can also get freckles on the lips, which may be a sign of a genetic condition known as Peutz-Jegher syndrome, associated
with a high risk of bowel cancer, and there are even rarer genetic conditions associated with lentigines (ephelides), which can look similar to freckles. Generally, though, freckles are perfectly normal and nothing to worry about.

Dr George Moncrieff

Dr George Moncrieff was a GP principal in Bicester from 1985 until 2017 when he retired from his NHS practice. He, is the Clinical Lead for a Community Dermatology Service in South Birmingham run by SDS MyHealthCare Federation. He also works in a private practice in Oxford up to one day a week as well as doing locums in General Practices for local practices.

From 1999 until he retired he ran an Interface Dermatology Service, receiving direct referrals from around 50 GPs in North Oxfordshire. He was the RCGP Dermatology Curriculum Guardian from 2010 until 2014, Chair of The Dermatology Council for England from 2014 until July 2018 and a PCDS Committee Member from 2005 until 2018. He remains the Primary Care Advisor to the National Eczema Society.

Originally published OCTOBER 06 2020
Originally published October 06 2020, updated February 18 2022

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