Type I hypersensitivity

Type I hypersensitivity
Type I hypersensitivity
Other names	Immediate hypersensitivity
	Image showing the mechanism of activation of type 1 hypersensitivity in a mast cell.
Specialty	Immunology

Type I hypersensitivity (or immediate hypersensitivity), in the Gell and Coombs classification of allergic reactions, is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen.^[1] Type I is distinct from type II, type III and type IV hypersensitivities. The relevance of the Gell and Coombs classification of allergic reactions has been questioned in the modern-day understanding of allergy, and it has limited utility in clinical practice.^[2]

Exposure may be by ingestion, inhalation, injection, or direct contact.

^ med/1101 at eMedicine
^ Descotes, Jacques; Choquet-Kastylevsky, Geneviève (February 2001). "Gell and Coombs's classification: is it still valid?". Toxicology. 158 (1–2): 43–49. doi:10.1016/S0300-483X(00)00400-5. PMID 11164991.

[1] med/1101 at eMedicine

[2] Descotes, Jacques; Choquet-Kastylevsky, Geneviève (February 2001). "Gell and Coombs's classification: is it still valid?". Toxicology. 158 (1–2): 43–49. doi:10.1016/S0300-483X(00)00400-5. PMID 11164991.

[1]

[2]