Skin and winter: what are the effects of the cold?

It is known today that exposure to wind and variations inhumidity influence the homeostasis of the skin barrier and therefore alter skin conditions, such as the water content of the stratum corneum and skin roughness. Indeed, it has been reported that a low humidity environment (<40%) like in winter can induce the appearance of fine lines, linked to a decrease in skin elasticity. In fact, a study conducted with 20 volunteers revealed a significant increase in fine wrinkles within 30 minutes after exposing the eyelid skin to low humidity compared to high humidity, and that this impact could increase with exposure time. In another study, men subjected to a state of chronic dryness showed significant changes in wrinkle depth during the winter season. In winter, the hydration state of the stratum corneum and the skin's extensibility is less. However, these biophysical parameters are crucial for maintaining its suppleness.

Another phenomenon that frequently occurs in winter, affecting anyone at any age is chapped lips. Apart from nutritional deficiencies, allergies, the use of certain medications or licking the lips frequently, low temperatures and dry weather are some of the reasons why lips can become cracked. Unlike other parts of the face, the skin of the lips is thinner and does not contain sebaceous glands, which increases the skin's susceptibility to drying out, cracking, stinging/burning, and even bleeding if not properly cared for.

The properties of the skin also evolve according to the ambient temperature, leading to vasomotor reactions and a disruption of the skin's barrier function. In addition to causing dry skin and itching, many people's skin can become red when exposed to a cold environment. Indeed, studies have shown a positive correlation between the outside temperature and the onset of redness.

The capillaries and blood flow alter with ambient temperature, particularly if you already suffer from a skin condition (rosacea, eczema, etc.). Indeed, exposure to harsh winter conditions can cause a contraction of the blood vessels, as well as a reduction in sebum production.

Furthermore, while during the cold seasons the skin loses a lot of moisture and the skin barrier is damaged, it no longer fulfils its protective function, thus becoming more vulnerable and reactive to environmental irritants and allergens, thereby inducing a mild skin inflammation. Indeed, an increase in the levels of pro-inflammatory cytokines (IL-α) and cortisol, as well as the number of dermal mast cells, has been observed.

We are now aware of the need to protect ourselves in the summer, but the same applies in winter. Precautions must also be taken to reduce the impact of winter aggressions on the skin. It is therefore essential to keep our hands, feet, face and any other part of our body protected from the cold to prevent the onset of symptoms and prevent their worsening.