Dry skin is a very common condition that increases with age and in locations with colder climates.
Dry skin is known medically as Xerosis — a very common condition that increases with age and in locations with colder climates. It manifests as flaky, dry, rough and uneven skin that sometimes has a cracked appearance and, in extreme cases, can bleed and become itchy.
It is a useful analogy to think of our outermost layer of skin, or the stratum corneum, as a brick wall. The bricks are our skin cells and the mortar is our natural oils or lipids. Together, they keep our skin working like a barrier to the outside world, preventing chemicals like allergens, irritants, and infectious particles from penetrating. More importantly, this barrier helps protect the skin from an onslaught of dehydration stress and environmental assaults leading to loss of water. Essentially, this brick wall helps keep hydration in.
Considering this brick wall is less that 20um thick, or half the diameter of a single shaft of hair, its function as a permeable membrane is an incredible by-product of human evolution.
Those factors that disturb the mortar of skin’s brick wall and allow water to escape are what cause our skin to become dry and flaky or, more illustratively, a crumbled brick wall.
RISK FACTORS
Environment and Climate
Cold weather is the most common cause of dry skin due to low outdoor humidity levels and heating systems that force hot and dry air indoors.
Air conditioner units used in warm weather can also induce dry skin since they strip moisture from the atmosphere. Dry skin can also be due to artificial air treatments, like those used in airplanes, that expose the skin to dry air and cause it to lose moisture.
Age
Dry skin is most common among older adults due, in large part, to an increase in enzymes that break down the natural “mortar” of the skin’s “brick wall.” In older skin, sweat and oil glands also decrease in number and effectiveness. These glands provide necessary building blocks to maintain the integrity of the skin.
Ethnic Variations
Darker pigmented skin appears to have superior skin barrier function. This is thought to be due to the lower pH of darker skin, which results in more building blocks and lipid content that can protect the skin from environmental assaults, compared to lighter skin.
Medical Conditions
Some patients have genetic conditions that lead to an abnormal brick wall from birth. In particular, patients with atopic dermatitis develop dry skin before they go onto have active dermatitis. It is now known that acne vulgaris (common acne) and acne rosacea can have a decreased skin barrier leading to dry skin and skin that is more intolerant to washing and topical medication.
Bathing and Showering
Water, along with the detergents found in soaps and cleansers, decrease the surface oils and lipids (the “mortar”) of the skin. Warm water is more effective at removing our skin’s natural oils than cool water. Friction from harsh toweling can also disturb our skin’s barrier function.
Soap and Cleansers
The most important aspect of soaps and cleansers as it pertains to maintaining a healthy skin barrier or brick wall is its pH — a logarithmic scale ranging from acidic (0) to alkaline (14) with 7 registered as neutral. It is a measure of the molar concentration of hydrogen ions in a solution.
Our skin is naturally acidic with an average pH of 5. Anything that disturbs this will result in damage to the skin’s barrier function, which can lead to dry skin.
The chemical reaction between detergent, water and skin is complex and the full impact on the skin pH and the skin microbiome is not fully understood. It is known that the detergents in cleansers damage the skin barrier because they cannot determine the difference between skin debris and the skin’s natural lipids.
Soap is a cleanser, but not all cleansers are soap. Cleansers can be classified based on the type of surfactant used. Soap-based cleansers are created when a fat, either animal or vegetable, interacts with a strong alkali, like lye. This chemical reaction, called saponification, creates a fatty acid salt which has a high pH usually around 9-10.
Syndet cleansers are the most commonly used cleansers today. These cleansers have a pH formulated to 5-7 which is closer to normal skin pH.
Medications
Some medications like diuretics, antiandrogens, and cholesterol lowering drugs, can predispose a patient to dry skin. Solvents such as alcohol can also dry the skin.
Fragrance
Fragrance, both synthetic and natural, is a known potential irritant. It can exacerbate already dry irritated skin and make it worse.
TREATMENTS:
Humidification: Replacement of humidity through the use of vaporizers or humidifiers can help prevent and treat dry skin
Avoid high pH soap bars and use pH adjusted syndet cleansers or lipid free cleansers that are fragrance free
Avoid antibacterial soaps and cleansers
Avoid fragrance, both synthetic or organic, in skincare and laundry care
Showering is better than bathing. Keep sessions short (between 5 and 10 minutes).
Consider showering on alternating days and only wash odorous regions of the body, including groin, underarms and feet
Wash with warm water instead of hot water
Blot or pat your skin dry after washing. Do not rub
Apply fragrance-free moisturizer immediately after washing. Use ointments or creams and oils rather than lotions
Ingredients that are beneficial for dry skin include, but are not limited to: lactic acid, urea, hyaluronic acid, dimethicone, glycerin, lanolin, mineral oil, petrolatum, natural oils (sunflower seed oil and virgin coconut oil)
Wear latex-free reusable gloves for all wet work or chemical exposure. Wear a cotton liner under the rubber glove
Moisturize your hands after every hand wash with a fragrance-free product
Avoid cold weather and wind and wear gloves to protect your hands
Choose fabrics that do not irritate the skin. Natural fibers, like cotton and silk, allow your skin to breathe
