SKIN BARRIER: 101
What is a skin barrier?
The stratum corneum is the outermost layer of your skin. It's made up of rigid corneocytes in a lipid matrix made up of cholesterol, fatty acids, and ceramides. It's basically a brick wall - the corneocytes are the bricks and the lipid matrix is the mortar. This layer acts as a physical barrier to keep out pathogens/irritants but also protects your skin from trans-epidermal water loss (TEWL).
Healthy skin barrier vs damaged skin barrier
When the skin barrier is damaged, the lipid matrix (the mortar) isn't as sturdy as it should be, leading to cracks and gaps. These cracks and gaps make it easier for irritants and germs to enter the skin. The cracks also make it easier for water to escape the skin (aka increased trans-epidermal water loss) - skin becomes dry and dehydrated, but those external interlopers can also contribute to inflammation.
Signs of a damaged skin barrier:
This is a tricky one as a lot of skin conditions share the same symptoms as a damaged skin barrier. Also, when your skin barrier is damaged, conditions like acne, eczema and rosacea can become more severe.
Most common symptoms include:
Dryness, redness, sensitivity, itching, flaking, burning, acne/breakouts, dullness, enlarged pores and pronounced fine lines/wrinkles.
What are the causes of a damaged skin barrier?
Causes of a damaged skin barrier can be separated into two groups...
Non-modifiable causes:
Genetics: this includes things like eczema, rosacea and dermatitis which are skin conditions commonly accompanied by a weaker skin barrier
Age: as you age your ability to produce oil decreases, making it more difficult to replenish skin lipids
Modifiable/avoidable causes:
Environment: UV rays, wind, pollution, indoor heating
Skincare: using the wrong products for your skin, over-exfoliating, washing too frequently, overuse of retinoids, overuse of acne products, using hot water
Lifestyle: smoking, drinking alcohol, excess caffeine, lack of sleep, excess stress
How to repair a damaged barrier?
So, you've overused your retinol and your skin is screaming. How do you fix it?
Stop all 'active' ingredients: this includes exfoliants, acids, retinoids, acne treatments and even vitamin C
Use a gentle cleanser: go for nourishing formulas and avoid anything that foams
Find a good barrier repair moisturiser: you want a moisturiser that uses humectants (to hydrate), emollients (to rebuild the barrier) and occlusives (to create a protective barrier over the skin). Look for ingredients like ceramides, cholesterol, fatty acids, shea butter, panthenol, petrolatum, aloe and glycerin
Be diligent with your SPF: UV rays impede the healing process so make sure you're applying (and reapplying) your SPF30+ daily
Be patient!!! It can take anywhere between 2 weeks to 6 MONTHS to repair a damaged skin barrier.