Rethinking the March as a Web, Not a Line
In this episode of SkinSync, host Buchi Neita, PA-C, and guest co-host Lisa Weiss, PA-C, sit down with allergist Dr. Payel Gupta to unpack the atopic march. As Dr. Gupta explains, the march is a progression from one atopic condition to the next, classically beginning with eczema in infancy and moving toward food allergy, asthma, allergic rhinitis, and sometimes eosinophilic esophagitis.
But she cautions against picturing it as a single-file line. While it was originally described as a linear, real-world progression, Dr. Gupta says the current understanding is that it is a non-linear clustering of type 2 inflammatory diseases. The order can vary, and patients may develop some or all of these conditions. She frames it as a web of interrelated conditions driven by a shared underlying immune pathway — not a series of separate diagnoses.
On genetics, Dr. Gupta notes that atopy is inherited as a predisposition, not a specific allergy. An atopic parent is more likely to have an atopic child, but that does not mean a parent's shrimp allergy passes down as a shrimp allergy. The child could develop any of the atopic conditions somewhere down the line — or none at all.
The Skin Barrier as the Starting Point
Dr. Gupta explains why the skin is so often where the march begins. As the body's largest barrier organ, the skin is the first line of defense between the immune system and the environment. In genetically predisposed patients, a filaggrin mutation compromises that barrier from birth. Filaggrin produces natural moisturizing factors and helps maintain the lipid matrix holding keratinocytes together; when it is deficient, transepidermal water loss increases and allergens become more permeable.
The result, she says, is an immune system that gets inundated with environmental factors and food through a route it shouldn't. Dr. Gupta shares a quote she now repeats constantly: 'Through the skin allergies begin, through the diet allergy stays quiet.' The immune system is supposed to meet food through the oral mucosa, mouth, and gut, where it learns tolerance. When it encounters food through a compromised skin barrier, it gets confused and reacts.
This framing, both Neita and Weiss note, is a powerful way to explain the stakes to hesitant parents. Weiss recounts a case with a toddler whose father was doing well on dupilumab; the mother was initially opposed but changed her mind once the barrier-repair rationale—and its connection to reducing future atopic conditions—was explained clearly.
Does Aggressive Eczema Treatment Alter the March?
Dr. Gupta believes early, effective eczema treatment can help interrupt the march by preventing initial sensitization through the skin. She cites a 2024 retrospective cohort study of over 4,300 pediatric patients in which dupilumab was associated with a 32% reduction in atopic march progression compared with conventional immunomodulators, a 40% reduction in new-onset asthma, and a 31% reduction in allergic rhinitis. She stresses these are retrospective data — not definitive proof — but the evidence points in a promising direction.
Neita draws a parallel to the 'window of opportunity' language popularized in hidradenitis suppurativa: catching patients early and getting them on therapy may reduce long-term disease. Dr. Gupta also reminds clinicians that untreated moderate-to-severe eczema robs children of sleep because of itch and discomfort, which can negatively affect development — one more reason to be adamant about early treatment and referral.
On emollients, Dr. Gupta separates two questions. Emollients remain essential for treating established eczema, but she notes the 2025 AAP clinical report found no role for recommending daily emollients to all infants to prevent atopic dermatitis. Prevention of established eczema, in other words, is not proven for universal emollient use — even though emollients stay central to managing existing disease.
Early Food Introduction and Smart Allergy Testing
Dr. Gupta is emphatic about early introduction of allergenic foods — something allergists have been 'screaming from the mountaintop.' As early as a child can start solids, with some studies pointing to around three months, families should think about introducing allergenic foods. Early exposure has been shown to reduce egg and peanut allergy, and allergists extrapolate that principle to other allergenic foods. She adds that oral immunotherapy started early in infancy can even shift some already-sensitized children toward non-allergy.
On testing, Dr. Gupta warns against panel testing atopic infants. Because these infants often have very high total IgE, broad food panels generate false positives that are difficult to untangle and require in-office oral challenges to sort out. She tests for a specific food only when the history clearly supports a reaction—for example, hives within 30 minutes of eating egg. For anxious parents, she'll even have them feed the child in the office where she can intervene. Reassuringly, she notes infant food reactions are usually isolated to the skin, with vomiting rare and breathing difficulty rarer still.
Dr. Gupta reserves patch testing for cases suggestive of contact dermatitis — perioral, periocular, or isolated hand dermatitis — rather than sending every atopic patient through the process. Environmental allergy testing, she says, is history-dependent and useful when symptoms clearly worsen with a new pet or follow a seasonal pattern with allergic rhinitis. On the hygiene hypothesis, she calls it genuinely confusing and full of confounders — and she is not telling patients to get a dog or eat off the floor.
Biologics and the Case for Co-Management
Dr. Gupta is enthusiastic about biologics, which finally give clinicians a real option for moderate-to-severe eczema patients who previously had little beyond head-to-toe topical steroids. She singles out dupilumab, which continues to accumulate approvals and is a 'no-brainer' for patients with overlapping type 2 conditions like asthma and eczema — a two-for-one. Still, she stresses that one size does not fit all: some patients don't respond to one biologic and need to switch, so more options are welcome.
Looking ahead, Dr. Gupta flags BTK inhibitors as a therapy to watch. Currently approved for chronic spontaneous urticaria, she expects additional indications for other type 2 conditions, and notes its oral formulation is appealing for patients who don't tolerate injectables.
Her closing message to dermatology APPs: dermatologists and allergists are strongest when they partner and co-manage. Many atopic patients carry one or more linked conditions, and communication across specialties — sometimes managing multiple diagnoses with a single medication or combination — is essential to treating the whole picture.