The Atopic March: Why It Stays on the Skin-Lung-Nose Track

The atopic march—eczema to asthma to allergies—seems like a predictable path, but why doesn’t it ever lead to rheumatoid arthritis or lupus? This episode unpacks the immune system’s two distinct misbehavior modes: type two inflammation (atopy) versus Th1/Th17 pathways (autoimmunity). We explore the "leaky skin" hypothesis, the role of epithelial barriers, and why the march can sometimes reverse direction. Discover how filaggrin mutations, environmental triggers, and age-related barrier changes determine which organ expresses the atopic predisposition. Plus, we examine why drugs like dupilumab work across barrier sites but fail in joints, revealing the biological boundaries between these disease clusters.