Atopy -

Atopy is a genetic predisposition toward developing exaggerated IgE-mediated immune responses to common environmental allergens. Clinically, it manifests as a triad of conditions—, allergic rhinitis (hay fever) , and allergic asthma —often appearing sequentially in a pattern known as the "atopic march". 1. Pathophysiology and Mechanism

The core of atopy is a Type I hypersensitivity reaction driven by a Type 2 immune response. allergic rhinitis (hay fever)

: Antigen-presenting cells perceive allergens (like pollen or dust mites) as danger signals, activating TH2 or ILC2 cells. allergic rhinitis (hay fever)

: These cells produce cytokines (IL-4, IL-13) that trigger B cells to differentiate into plasma cells producing allergen-specific IgE. allergic rhinitis (hay fever)

Atopy typically follows a predictable chronological progression: