Skin prone to rosacea: how to combat the assaults of the cold?

Intense skin dryness, discomfort, redness... rosacea is characterised by damage to the skin barrier leading to an increase in transepidermal water loss. However, during the winter period with the cold and dry air, the skin is even more dehydrated, and the blood vessels tend to contract in response to the cold, further enhancing the appearance of redness. The skin becomes more inflamed due to the proliferation of certain inflammation markers and thickens at the level of the horny layer, thus reducing its suppleness.

However, in response to the effects of cold, good hydration can promote the maintenance of the skin barrier's integrity by creating a protective film on the skin's surface. This limits water loss and maintains a sufficient level of skin hydration. Consequently, the use of certain occlusive agents (silicones, waxes, butters, etc.) and humectants (hyaluronic acid, glycerine, etc.) should be prioritised. Emollient agents (ceramides, squalane, vegetable oils and butters, etc.) should also be encouraged, as they will provide a reinforcement of the skin barrier. These agents will retain the skin's moisture while promoting its protection.

Furthermore, the use of active ingredients such as niacinamide can also help to repair the skin barrier. It can improve the structure of the epidermis by increasing the production of lipids, such as ceramides. In addition, anti-inflammatory actives, such as azelaic acid, can reduce visible redness, stabilise blood vessels, and have a soothing effect. These actives help to restore the function of the skin barrier, thus leading to a reduction in irritation and redness.

Exposure to cold activates a pathway of channels known as TPR, and particularly the TRPA1 channel. This latter plays a pivotal role in detecting temperatures and signalling them to the peripheral nervous system. However, a drop in temperature will trigger the activation of nociceptive neurons called ANKTM1. In response to the cold, the vascular system causes vasodilation, resulting in more intense redness.

In order to protect the skin from exposure to the cold, it is necessary to cover up. As the majority of rosacea symptoms affect the face, it is important to cover up by wearing a hat and a scarf covering the affected areas (chin and cheeks), or, in cases of extreme cold, to favour wearing a balaclava.

In the face of the cold outdoor climate, hot showers and baths can be comforting in winter. In the same way that the neuro-receptors present on the skin's surface detect drops in temperature, high temperatures can also cause a disruption to the skin barrier.

Just like the cold, excessive heat is equally a trigger factor for rosacea. Responsible for activating the TRPV1 and TRPV2 pathway, excess heat selectively stimulates sensory neurons that signal variations to the nervous system.

These neurons are responsible for the sensation of pain experienced in the event of a burn. The body stores the heat, thereby triggering the dilation of blood vessels on the skin's surface in order to dissipate it. The heat will also increase water loss, thus promoting dehydration.

In the case of rosacea, it is particularly recommended to avoid hot showers and baths in order to limit the development of these symptoms. Steam rooms and saunas should also be avoided due to the hot vapours they produce.

Similar to hot showers and baths, heating can be a source of excessive heat. Indeed, through the activation of TRPV1 and TRPV2 pathways, blood flow will increase and exacerbate the appearance of rosacea symptoms. Therefore, despite the sensation of cold, it is preferable for individuals suffering from rosacea to limit indoor heating. The ideal is to maintain a surrounding temperature of around 17 to 18°C.

Both outdoors and indoors, the dry winter air can promote skin dehydration, leading to irritations and feelings of tightness. The use of an air humidifier can help to offset this loss of moisture in the air and thus assist in maintaining a 30 to 50% indoor humidity level. The use of this tool can therefore limit water loss and skin dryness.

Coffees, hot chocolates, soups, mulled wines... winter is a season conducive to the consumption of hot beverages for their comforting aspect. However, the intake of these types of drinks causes an excessive supply of heat to the body, creating a sensation of overheating.

This phenomenon utilises the same mechanisms as those previously mentioned. The body will attempt to dissipate heat on the surface, the blood vessels will dilate and induce significant erythema. Thus, very hot drinks should be limited for people affected by rosacea, it is preferable to consume drinks at room temperature.

The consumption of alcohol can lead to an increase in the production of pro-inflammatory cytokines, thereby increasing the risk of inflammation and associated symptoms. Alcohol also promotes the release of catecholamines, causing vasodilation in the face. Alcohol consumption is ideally to be limited in the case of rosacea. It is preferable to limit its consumption to one glass per week.

Spicy foods such as pepper, mustard or chillies contain a molecule, capsaicin, which is responsible for the sensation of spiciness and the associated heat flushes when consumed. Indeed, this molecule stimulates the activity of the TRPV1 receptor and triggers the release of the neuropeptides PACAP and CGRP through nociceptive mechanisms.

These neuropeptides in turn induce the dilation of blood vessels, which is the cause of the redness found in rosacea. Besides the consumption of chillies, spicy foods like garlic can also be the cause of such effects. The molecule responsible for this phenomenon in garlic is allicin. It operates following the same mechanisms as capsaicin.

Given that it contributes to the increase in inflammation and exacerbates skin redness and irritation, the consumption of spicy foods should be minimised as much as possible, especially during this period when the skin is even more sensitive.

Some cosmetic products can cause bothersome reactions, such as itching, irritation, skin dryness, flaking, or even burning sensations. They can further sensitise the skin and induce disturbances in the skin barrier, making the skin more vulnerable to external aggressions such as cold.

In order to avoid these types of adverse reactions, it is recommended not to use cosmetics containing these aromatic components, particularly essential oils which should be avoided. Furthermore, the use of products containing alcohol or synthetic fragrances is also to be discouraged, as they have a drying effect and can cause irritations.