Type I hypersensitivity

Definition

Type I hypersensitivity is an immediate allergic reaction mediated by IgE antibodies that occurs upon exposure to a specific antigen. It involves mast cell degranulation and the release of histamines and other inflammatory mediators.

5 Must Know Facts For Your Next Test

1. Type I hypersensitivity reactions can occur within minutes of exposure to the allergen.
2. Common examples include allergic asthma, hay fever, and anaphylaxis.
3. IgE antibodies bind to allergens and trigger mast cells and basophils to release histamine.
4. The severity of Type I hypersensitivity can range from mild symptoms like itching and sneezing to severe reactions such as anaphylactic shock.
5. Skin prick tests are commonly used to diagnose Type I hypersensitivities.

Review Questions

Related terms

IgE Antibodies: Immunoglobulins specifically involved in allergic reactions and parasitic infections.

Mast Cells:

Immune cells that release histamine and other chemicals during inflammatory and allergic responses.

Anaphylaxis:

A severe, potentially life-threatening allergic reaction characterized by rapid onset.