By: Rene Maserati
Does your face hurt in the winter? Does your skin feel dry, itchy, irritated? Like it might crack if you smile too hard? Here are some tips for keeping your skin feeling soft and supple in the cooler weather.
But first…a bit about the structure and function of the skin we present to the world.
One of the many important functions of the skin is to act as the body’s first line of defense against external factors like bacteria, pathogens, chemicals, UV radiation, and mechanical trauma like cuts, scrapes, and abrasions. This defense mechanism is referred to as the skin barrier function.
A good way to visualize the players involved in keeping the bad guys out is to imagine bricks and mortars. The ‘bricks’ are the dead and dried out skin cells (keratinocytes) that become corneocytes as they make their way to the outermost layer of the skin, also known as the stratum corneum, or SC. They contain enzymes that help maintain the acidic pH of the skin, proteins, antimicrobial peptides, and melanin to protect from UV radiation. The ‘mortar’ is the lipids and ceramides that are squeezed out of the skin cells as they make their way from the lower layers of the epidermis to the SC.
Schematic diagram of the epidermis
From the inside-out, the skin helps regulate water loss through evaporation. This process is called trans epidermal water loss, or TEWL. TEWL is dictated by the water vapor pressure gradient both internally and external to the skin.
(** Nerd Alert! **) The deeper dermal layers of the skin contain more water and thus create a gradient that pushes water up towards SC. This is a naturally occurring process with water evaporating on the skin’s surface on average 300-400 mL per day. (About 10-12 fluid ounces, like a Poland Spring water bottle). So TEWL isn’t a bad thing. It helps us from overheating and keeps our body temperature regulated. But too much TEWL can dry you out.
This diffusion of water, from the dermis to the SC, is controlled by a healthy SC. Any damage to the SC can compromise barrier function, diminishing the skin’s ability to effectively retain water in the SC and increases TEWL.
The ‘bricks’ that make up the SC retain water along with natural moisturizing factors (NMF’s- Best name ever!) that are also found in the corneocytes. When hydration is maintained in the SC, the skin stays flexible, elastic, and supple. Insufficient SC hydration result in lackluster, flaky, irritated skin that is less effective at protecting the body from harmful chemicals and pathogens.
Low humidity and windy conditions in the wintertime can increase TEWL, potentially causing dry, irritated, flaky skin with a compromised skin lipid barrier function. Skin may become dull looking and fine lines may become accentuated. Increase in TEWL has also been linked to chronic inflammatory skin conditions like atopic dermatitis and psoriasis.
So that’s all great…thanks for the skin physiology lesson. But what can I do to help my dry skin?!
Tips To Help Dry Skin
Moisturize with a formulation that contains a synergistic blend of humectants, emollients and occludents for the winter months and reapply regularly. Like if you just took a walk on a cold windy day, or after skiing.
Humectants attract and hold water in the skin, drawing it up from the dermis or from the air. Look for ingredients like hyaluronic acid, urea, panthenol, or glycerin.
Emollients give the moisturizer a nice feel and help fill in the spaces between corneocytes on the stratum corneum. Look for ingredients like squalene, linoleic acid, stearic acid, and oleic acid.
Occludents are oils and waxes that sit on the skin and physically block TEWL. While they may not be considered a good option for those with oily/acne-prone skin, those with a dry skin type may find relief as ingredients like dimethicone, beeswax, lanolin, and mineral oil help reinforce the skin’s barrier.
Switch up your cleansing routine. Opt for a gentle cream-based cleanser in the cooler weather to help maintain a healthy skin barrier function. Limiting shower time and using lukewarm water for rinsing instead of hot water helps keep the skin hydrated and reduces TEWL from occurring.
Humidify the air. A cool water mist humidifier helps to keep the water vapor pressure gradient outside the skin at an optimal level to keep skin soft and supple. Indoor plants love it too!
Skip harsh exfoliation. Over-exfoliating in the cooler weather can compromise the skin barrier with excessive removal of the SC, leaving the skin vulnerable to bacteria, UV damage and hydration loss. A clay-based mask once a month should be sufficient for most skin types at gently sloughing off spent skin cells while leaving the SC intact. Occasional use of toners or lotions with alpha hydroxy acids like lactic acid may be beneficial for those with a dry skin type that may need a little more help in the winter. The key to any exfoliation, regardless of the time of year, is to not over-do it.
Stay tuned for the next blog for our favorite picks to help winter skin stay hydrated!
References
Images
Woman in winter Photo by Fransiskus Filbert Mangundap on Unsplash
Schematic diagram of epidermis- https://karger.com/spp/article/34/3/146/296024/Corneocytes-Relationship-between-Structural-and
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