What's the difference between dry skin and healthy skin

What's the difference between dry skin and healthy skin

What's the difference between dry skin and healthy skin blog

The skin barrier

The skin barrier serves two primary functions: keeping moisture in and keeping irritants and allergens out. It is comprised of flattened, dead cells (corneocytes) embedded in layers of lipids in what’s often described as a ‘brick and mortar’ motif.[1] When the skin is healthy and hydrated, the barrier functions normally, but if the structure is compromised, either through disease, exposure to irritants or extreme dryness the barrier loses its strength.

What's the difference between dry and healthy skin - Image 1
What's the difference between dry and healthy skin - Image 2
What's the difference between dry and healthy skin - Image 3

Causes of dry skin

  • Skin conditions (such as psoriasis and eczema)[2]
  • Environment (cold weather and low humidity, dry wind, summer sun, air conditioning)[3]
  • Some medications (such as cholesterol-lowering agents, anti-acne medication, diuretics)[4]
  • Irritants (such as frequent use of soap and water or solvents)[4]
  • Age (nearly everyone over the age of 60 is affected by dry skin)[5]
  • Vitamin or mineral deficiency (low levels of vitamins D & A, niacin, zinc or iron can contribute to dry skin)[4]
  • Lifestyle choices (like smoking and prolonged UV exposure)[4]


Signs and symptoms of extremely dry skin[6]

  • Loss of colour - areas of dry skin may appear a grey-white colour, making fine lines and wrinkles in the skin more visible.
  • Scaling and flaking - as corneocytes dry out, cohesion between the cells is reduced, causing them to flake off.
  • Rough or dull appearance - skin feels rough and has a dull appearance as it is less able to refract light than smooth skin.
  • Loss of elasticity - dry skin becomes less pliable and may appear to have a wrinkled, rough or loose texture[6,7]
  • Cracks and fissures - when skin becomes extremely dry, deeper cracks or fissures may form as a result of reduced elasticity
  • Pruritus - dry skin is more prone to itch[8]


A breakdown in the barrier function of the skin:

  • Can lead to dry skin, which may become flaky and even cracked
  • Allows for the entry of irritants/allergens, increasing the potential for irritation
  • Is associated with skin conditions such as dermatitis and eczema Proper hydration absolutely critical in maintaining healthy skin.[9]

One study showed that simple, or poorly formulated moisturisers can have a negative effect on the skin barrier over time, while a ‘complex’ moisturiser containing a blend of moisturising agents, reduced water loss from the skin.[10]

There are three distinct types of moisturising ingredients: humectants, emollients, and occludents. When combined, they work together to mimic the way skin naturally moisturises itself.[11]

  • Humectants – act like molecular sponges that attract and hold water in the outer layers of the skin.
    Glycerin - Glycerin transport, through AQP3 channels in the skin, has a direct impact on improving skin hydration, elasticity and barrier function recovery.[12]
  • Emollients – Help lubricate skin, swelling skin cells and closing cracks
    Paraffinum Liquidum - Fills spaces between skin flakes, smoothing dry skin
    Dimethicone – Protects against water loss
    Squalane – Helps restore suppleness and flexibility to skin
  • Occludents – Form a near-waterproof film on the skin that keeps water in, reducing trans-epidermal water loss (TEWL)

Petrolatum – can help reduce TEWL by up to 99%[13]



  1. Harding CR. The stratum corneum: structure and function in health and disease. Dermatol Ther 2004;17(s1):6–15
  2. Augustin M, Wilsmann‐Theis D, Körber A, Kerscher M, Itschert G, Dippel M, et al. Diagnosis and treatment of xerosis cutis – a position paper. JDDG J Dtsch Dermatol Ges 2019;17(S7):3–33
  3. Engebretsen KA, Johansen JD, Kezic S, Linneberg A, Thyssen JP. The effect of environmental humidity and temperature on skin barrier function and dermatitis. J Eur Acad Dermatol Venereol 2016;30(2):223–49
  4. Dry skin: Who gets and causes [Internet]. Am. Acad. Dermatol. [cited 2020 Nov 4];Available from: https://www.aad.org/public/diseases/a-z/dry-skin-causes
  5. Oakley A. Dry skin [Internet]. DermNet NZ2015 [cited 2020 Oct 26];Available from: https://dermnetnz.org/topics/dry-skin
  6. Sevrain S, Bonte F. Skin hydration: a review on its molecular mechanisms. J Cosmet Dermatol 2007;6:75–82
  7. Pedersen LK, Jemec GBE. Plasticising effect of water and glycerin on human skin in vivo. J Dermatol Sci 1999;19:48–52.
  8. Hara-Chikuma M, Verkman A. Physiological roles of glycerol-transporting aquaporins: the aquaglyceroporins. Cell Mol Life Sci 2006;63:1386–1392
  9. Brettmann EA, Strong C de G. Recent evolution of the human skin barrier. Exp Dermatol 2018;27(8):859–66
  10. Buraczewska I, Berne B, Lindberg M, Törmä H, Lodén M. Changes in skin barrier function following long-term treatment with moisturizers, a randomized controlled trial. Br J Dermatol 2007;156(3):492–498
  11. Greive K. Cleansers and moisturisers: the basics. Wound Pract Res J Aust Wound Manag Assoc 2015;23(2):76
  12. Greive K. Glycerine: the naturally effective humectant. Dermatol Nurs 2012;11(1):30–34.
    Draelos ZD. The science behind skin care: Moisturizers. J Cosmet Dermatol 2018;17(2):138–44


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