Type I reactions (i.e., immediate hypersensitivity reactions) involve immunoglobulin E (IgE)–mediated release of histamine and other mediators from mast cells and basophils. Examples include anaphylaxis and allergic rhinoconjunctivitis.

What type of hypersensitivity is anaphylaxis?

Type I hypersensitivity reactions can be seen in bronchial asthma, allergic rhinitis, allergic dermatitis, food allergy, allergic conjunctivitis, and anaphylactic shock. Anaphylaxis is a medical emergency as it can lead to acute, life-threatening respiratory failure. It is an IgE-mediated process.

What is a Type 1 hypersensitivity reaction?

Type I hypersensitivity is also known as an immediate reaction and involves immunoglobulin E (IgE) mediated release of antibodies against the soluble antigen. This results in mast cell degranulation and release of histamine and other inflammatory mediators.