Atopy typically follows a predictable chronological progression:
: Often the first sign in infancy, caused by skin barrier defects (e.g., filaggrin mutations) that allow for epicutaneous allergen sensitization. Clinically, it manifests as a triad of conditions—,
The core of atopy is a Type I hypersensitivity reaction driven by a Type 2 immune response. allergic rhinitis (hay fever)
: Upon re-exposure, allergens cross-link IgE on the surface of mast cells, causing degranulation and the release of inflammatory mediators like histamine and leukotrienes. 2. The Atopic March activating TH2 or ILC2 cells.
: Sensitization through inflamed skin can lead to early-onset food allergies.
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
: Antigen-presenting cells perceive allergens (like pollen or dust mites) as danger signals, activating TH2 or ILC2 cells.