THE ANATOMY OF WINTER SKIN

THE ANATOMY OF WINTER SKIN

As the temperature drops, many notice their skin begins appearing dry, scaly, and dull. For some, dehydrated skin presents itself mildly, while others encounter severe manifestations of a skin condition known as eczema. This yearly occurring skin condition isn’t always the result of extreme temperature drops or low humidity—it’s a multifactorial entity that can be caused by both endogenous (inside the body) or exogenous (outside of the body) sources.

The exogenous factors include climate changes, exposure to electric heat sources, the use of pH imbalanced soaps or surfactant based cleansing agents. While the causes of dry skin are often addressed topically, the anatomy behind the condition usually receives less recognition or understanding.

There are several terms for dry skin (xerosis cutis, xeroderma, asteatosis), but all essentially refer to a condition where the skin lacks moisture. It can affect individuals of any age, but it is more common as we age when sebaceous gland activity decreases, and our skin subsequently produces less natural oil.

STRATUM CORNEUM

Essentially xerosis cutis is a result of defects in the stratum corneum— the outermost layer of the epidermis, which is an inert water-retaining layer that is in a constantly dynamic state, as it is in a constant state of renewal.

The stratum corneum is composed of corneocytes (keratin-based proteins that regulate hydration) and lipids. The stratum corneum is composed of several elements that keep skin moisturized by preventing transepidermal water loss (TEWL). Some of these include:

1) Lipid content (including ceramides and hyaluronic acid--similar to what’s in your joints)

2) Natural Moisturizing Factor (NMF) contained in corneocytes which binds water

3) Transepidermal flow, which maintains water content throughout the skin. Tansepidermal flow is influenced by the extent of water evaporating at the skin surface known as transepidermal water loss.

CELLULAR RENEWAL

Approximately one layer of cells of the stratum corneum is lost every day and replaced by a new layer of underlying epidermal cells—a process known as desquamation. This regulated process replaces lifeless cells with new, healthier cells from deeper tissue layers. Desquamation begins when proteinases (enzymes that degrade proteins) interact with the cohesive forces that bind the corneocytes to the stratum corneum. Once separated, these cells can more easily be shed, replaced with new cells.

Factors in dry skin

So what defects lead to xeroxis cutis? A disruption in the maturation of the stratum corneum or interference with desquamation results in dry skin. Several factors are correlated with this disruption, including a decrease of certain hormones (perimenopause and thyroid disease), impaired barrier function, abnormal keratinization, lack of water in the stratum corneum, and inadequate lipid synthesis. One theory is that as we age, the normal enzymatic activity of protease is inhibited—this keeps the corneocytes from separating during desquamation. As a result, cellular renewal occurs at a much slower rate, which produces the classic flaky appearance consistent with the clinical presence of dry skin. However, most cases of xeroxis are easily treatable with topical moisturizers or procedures which help facilitate cellular renewal.

COPMPREHENSIVE ESTHETIC EVALUATION

Visit Unite, and allow a skin care professional to talk with you about your wishes and desires. She will carefully examine you and determine the present condition of your skin. Once the nature, behavior, and condition of your skin are understood, she will provide you with her opinion about how you can address both the internal and external hydration levels of your skin.