Defining the Barrier — and Why Clinicians Should Own the Conversation
PA Shanna Miranti opens by acknowledging that the skin barrier is having a cultural moment — front and center on Instagram and TikTok — but warns that influencers have partly co-opted it to sell products. Her point is that dermatology clinicians own this space, and the conversation is worth keeping grounded in science.
She then explains that the barrier isn’t one thing but several. Using the familiar brick-and-mortar analogy, she describes the physical barrier of keratinocytes and lipids that limits transepidermal water loss, plus the chemical (acid mantle) barrier that keeps skin at its naturally acidic pH — the reason she steers patients away from old-school basic bar soaps. She rounds out the picture with the microbiome barrier, the immunological barrier, and the photoprotective barrier provided by melanin and melanocytes.
Barrier Dysfunction as Driver, Not Just Consequence
When Miranti raises whether barrier dysfunction as a disease driver has been historically underestimated, Cheever agrees it has. Not long ago, barrier problems were viewed as a secondary consequence of inflammation; now the relationship is understood to be bidirectional — outside-in (barrier to inflammation) and inside-out (inflammation to barrier).
Eileen explains the mechanics in AD: a disrupted brick-and-mortar lets antigens penetrate more easily and kick off the immune cascade; patients have decreased antimicrobial peptides that predispose them to staph colonization and secondary infection; and skin pH can climb toward 7 when skin prefers roughly 5 to 5.5. From the inside out, the TH2 inflammatory milieu disrupts barrier gene proteins and keratinocyte differentiation.
Miranti ties the stakes to prevention, quoting Dr. Peter Leo's citation of Dr. Ruchi Gupta: "Through the skin, allergies begin, and through the diet, they stay quiet." Her takeaway is that addressing the barrier early — with hydration, emollients, and barrier-supportive prescription therapies — may help interrupt the atopic march, and even when it doesn't, it reduces flare severity and lengthens the intervals between flares.
Repair and Suppression Are Complementary, Not Competing
Eileen frames barrier repair and inflammation suppression as complementary goals to address together. Timing matters, though: with a patient acutely flaring, she uses the analogy that you don't fireproof a house while it's on fire — get them off the ledge first, then dive into the nitty-gritty of restoring and maintaining the barrier during maintenance.
Both hosts note that even patients on systemics, biologics, or JAKs still have barrier breakdown that needs good topicals and OTCs. Eileen flags the classic maintenance pitfall — patients feeling so good they let fragranced or perfumed products creep back into the shower and medicine cabinet — and recommends routine touchpoints, even asking patients to bring photos of their products to reconcile what they're using.
On measuring success, Eileen looks for less erythema, less itch, less scale and lichenification, and fading post-inflammatory hyperpigmentation. She points to longitudinal data suggesting that flare frequency and lengthening intervals between flares are among the most reproducible indicators of barrier improvement. Miranti adds tolerability as a real-world marker — patients who once couldn't wash their face without burning or stinging can do so once the barrier improves.
What the Newer Topicals Bring to the Barrier
Eileen contrasts newer agents with topical corticosteroids, which she notes rely on penetration enhancers that drive through the lipid barrier and can be very irritating — targeting epidermal lipid production and decreasing corneodesmosome density in the stratum corneum. She cites literature suggesting that even three days of a class 1 topical corticosteroid can meaningfully impact the barrier.
For tapinarof, approved for psoriasis and atopic dermatitis down to age two, Eileen explains the AHR agonist mechanism: it promotes encoding of barrier protein genes such as filaggrin, loricrin, and involucrin, and activates the NRF2 pathway to boost antioxidant activity against the oxidative stress seen in AD. She notes the active ingredient itself—not just the vehicle—changes the lipid layer, and shares the molecule’s origin story: a microbe, P. luminescens, found with a nematode.
For roflumilast, approved for atopic dermatitis, seborrheic dermatitis, and psoriasis at multiple ages, Miranti highlights the therapeutic vehicle: formulated without propylene glycol or aggressive penetration enhancers, with a multivesicular emulsion for even distribution, physiologic lipids, and a skin-like pH. She references a roughly 40-patient split-leg study in asteatotic eczema comparing the vehicle to a popular ceramide-rich OTC moisturizer, where after 17 days both reduced transepidermal water loss and increased hydration — meaning the vehicle performed comparably to an OTC moisturizer.
On topical JAKs, Eileen cites a 2025 ex vivo human skin explant study of ruxolitinib showing increased barrier gene proteins (filaggrin, filaggrin 2, loricrin) and decreased expression of the IL-13 receptor alpha-1 — consistent with ruxolitinib's JAK1/JAK2 inhibition near the IL-13 receptor. She hypothesizes that delgocitinib, a pan-JAK inhibitor, could theoretically produce a similar barrier and IL-13 effect, while noting that this is a hypothesis as of the date of the conversation.
Explaining Barrier Repair to Patients — and Improving Adherence
Both hosts stress simplicity and positive, forward-looking language. Eileen avoids telling patients their skin is "bad" or "not working," gently redirects away from disruptive products, and keeps the relationship trusting for what she sees as a lifelong connection. She likes the brick-and-mortar image — "a little extra space between those bricks" that lets irritants and allergens in — as the foundation for choosing better products.
Miranti favors going back to basics with a written plan and open-ended questions: how they shower, how often, how long, and what they use, without leading questions or assumptions. She offers handouts and samples, acknowledging some patients have sensory preferences and need to test a moisturizer before committing. Eileen ties the plan back to the patient's own complaints — less itch, less redness, being able to wear short sleeves in summer — to build buy-in.
Finally, the hosts note that steroid phobia — nearly universal among parents of infants and young children — makes newer nonsteroidal agents especially valuable. With a stronger safety profile, clinicians can spend energy reconciling the medicine cabinet rather than negotiating steroid fears, and can honestly say they'd use these agents on their own kids. Eileen closes on the episode’s theme: it's bidirectional, and you can't address one side without the other.