Hypersensitivities Overview

This flashcard set covers key concepts related to hypersensitivity, including definitions, types, and examples.

Hypersensitivity

An altered immunological response to an antigen that results in disease or damage to the host.

Antigen

A substance that the immune system identifies as foreign; an antibody generator.

Sensitization

The process of the immune system becoming responsive to an antigen after initial exposure.

Type I Hypersensitivity

IgE mediated hypersensitivity characterized by immediate reactions such as allergic rhinitis and anaphylaxis.

Type II Hypersensitivity

Tissue specific hypersensitivity involving IgG and IgM that leads to cell destruction and tissue damage.

Type III Hypersensitivity

Immune complex mediated hypersensitivity that results in tissue damage and inflammation due to antigen-antibody complexes.

Type IV Hypersensitivity

Cell-mediated hypersensitivity that typically occurs with a delay involving T cells and does not involve antibodies.

Immediate Reaction

Hypersensitivity response that occurs within minutes to a few hours after exposure to an antigen.

Delayed Reaction

Hypersensitivity response that occurs hours to days after exposure to an antigen.

Anaphylaxis

A severe, life-threatening allergic reaction characterized by difficulty breathing, vasodilation, and fluid shifts.

IgE Antibody

An antibody associated with allergic responses, particularly noted in Type I hypersensitivities.

Mast Cells

Cells that release histamines and other mediators during allergic reactions, causing symptoms like vasodilation and bronchoconstriction.

Genetic Component

Factors involved in the inheritance of hypersensitivity traits, often observed in atopic (Type I) allergies.

Graves' Disease

An autoimmune disorder and example of Type II hypersensitivity leading to overactivity of the thyroid gland.

Serum Sickness

A Type III hypersensitivity reaction caused by the formation of immune complexes that can lodge in tissues.

Contact Dermatitis

A local inflammatory reaction that occurs with Type IV hypersensitivity, often due to exposure to allergens like poison ivy.

Desensitization Programs

Therapeutic strategies to build IgG antibodies against allergens to reduce allergic responses.

Autoimmunity

A condition in which the immune system mistakenly attacks the body's own cells, often related to hypersensitivity.

Skin Testing

A diagnostic method used to evaluate hypersensitivity reactions by exposing skin to allergens.