Eases allergy load
You want it low: calmer airway reactivity means easier, clearer breathing.
In depth
Airway reactivity — the type-2 inflammatory response behind allergic breathing. A possible sign reversal: the same immune slant may increase resistance to some viruses while worsening allergy.
What drives it
Calms histamine response increases it.
Asthma histamine review 2019 — allergic asthma is driven by IgE-mediated mast-cell degranulation; released histamine causes bronchoconstriction, mucus secretion and airway edema. PMC6480561
Inflammatory signaling increases it.
In childhood neutrophilic asthma, Th17 frequency and sputum IL-17/IL-8 are elevated and correlate with sputum neutrophils (PMC7789788) — which is why this pathway sits beside the mast-cell one rather than replacing it: they describe two different asthma phenotypes. PMC7789788
Innate immune sensor increases it.
Endotoxin in inhaled air acts through TLR4: signaling in pulmonary stromal cells is required for early chemokine production, neutrophil and dendritic-cell recruitment to the lung and direct bronchoconstriction, and TLR4 signaling on epithelial cells induces a Th2-polarising response through Th2-inducing dendritic cells (PMC3189122). Inhaled endotoxin is thus a driver of airway inflammation in asthma, not merely a marker of it. MOUSE/stromal-cell work. PMC3189122
Calm skin barrier increases it.
10.1016/j.jfma.2020.02.014 — the atopic march - atopic dermatitis precedes asthma and allergic rhinitis in the classic progression. doi 10.1016/j.jfma.2020.02.014
Allergic signaling increases it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Immune support reduces it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Skin reduces it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Cell migration switch increases it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Pathogen tripwire increases it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Calms body-wide inflammation increases it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Calms inflammation increases it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Oxidative stress increases it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses (PMC11059040; PMC12263562; PMC11045947; PMC11897119; PMC12021798). Verbatim: “Among these mediators, endogenous or exogenous ROS are responsible for the airway inflammation of allergic asthma”. doi 10.21037/jtd.2017.01.05 · PMC11059040
Gut barrier reduces it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
Tissue remodeling reduces it.
This is the same axis as eczema, and it splits the same way: type 2 endotypes are IL-4/IL-5/IL-13-driven and eosinophilic, while non-type-2 endotypes ARE driven by increased Th1 and Th17 responses, resulting in elevated neutrophil levels. Two endotypes, two cell types, two nodes. And the intervention evidence is unusually direct: dupilumab (IL-4Ralpha inhibitor) reduces polyp burden and restores smell, while MEPOLIZUMAB (anti-IL-5) and OMALIZUMAB (anti-IgE) address specific endotypes - three biologics, three targets, three endotype-matched responses. PMC11059040
What it drives
It increases Calm skin barrier.
Named across six reviews of atopic dermatitis and psoriasis as part of the shared barrier-inflammation mechanism set. (PMC11007107; doi 10.3389/fimmu.2025.1541776; PMC7432778; PMC7072946; PMC11312859). REFUTED ON A SECOND READING. This link was shown by linked steps until a source was opened that does not support it: “AD is the first step of the “atopic march” that progresses into food allergy, allergic rhinitis, and asthma.” — Preclinical Models of Atopic Dermatitis Suitable for Mechanistic and Therapeutic Investigations. Journal of Inflammation Research, 2024, 17, 6955-6970. [DOI not present in the record and NOT derived]. doi 10.3389/fimmu.2025.1541776 · PMC11007107
It reduces Sleep.
Nocturnal symptoms disrupt sleep. PMC12446768
It reduces Physical performance.
Airway limitation constrains exercise capacity. PMC12446768
It increases Clears blocked nose & sinuses.
The united-airway relationship read the other way - the two co-occur and each worsens the other. PMC12446768
It reduces Mood.
Symptom burden and activity limitation. Low. PMC12446768
It increases Calms body-wide inflammation.
Type 2 inflammation is not confined to the airway - the same axis operates in skin and gut. PMC12446768
It reduces Supports airflow & lung function.
10.1186/s13223-019-0388-4 — Drawn from reviews of neighboring outcomes rather than from studies of this outcome itself, which is weaker evidence, and the map marks it so. doi 10.1186/s13223-019-0388-4
Blends that modulate it
Each blend page names this pathway and carries the study behind its claim.
See it on the map
Open the causal map to follow this pathway upstream and downstream, arrow by arrow, each with its study.