Chamberlain University NR 507 Advanced Pathophysiology
Hypersensitivity Reactions: Pathophysiology and Clinical Findings
Hypersensitivity Reactions: Pathophysiology
and Clinical Findings
Introduction
This case study focuses on hypersensitivity reactions, which are exaggerated
immune responses that occur when the body reacts inappropriately to foreign
substances or self-antigens. The purpose of this analysis is to explain the
underlying pathophysiology of hypersensitivity reactions and identify the
associated clinical manifestations commonly observed in affected patients.
Pathophysiology of Hypersensitivity Reactions
Hypersensitivity reactions occur when the immune system mounts an excessive or
inappropriate response to an antigen, resulting in tissue damage. These reactions
are classified into four types based on the underlying immune mechanisms.
Type I (Immediate Hypersensitivity) is mediated by immunoglobulin E (IgE).
Upon exposure to an allergen, IgE binds to mast cells and basophils, causing the
release of histamine and other inflammatory mediators. This leads to vasodilation,
bronchoconstriction, and increased vascular permeability.
Type II (Cytotoxic Hypersensitivity) involves immunoglobulin G (IgG) or
immunoglobulin M (IgM) antibodies binding to cell surface antigens, leading to
complement activation and cell destruction.
Type III (Immune Complex Hypersensitivity) occurs when antigen–antibody
complexes deposit in tissues, triggering inflammation and tissue injury through
complement activation.
Hypersensitivity Reactions: Pathophysiology and Clinical Findings
Hypersensitivity Reactions: Pathophysiology
and Clinical Findings
Introduction
This case study focuses on hypersensitivity reactions, which are exaggerated
immune responses that occur when the body reacts inappropriately to foreign
substances or self-antigens. The purpose of this analysis is to explain the
underlying pathophysiology of hypersensitivity reactions and identify the
associated clinical manifestations commonly observed in affected patients.
Pathophysiology of Hypersensitivity Reactions
Hypersensitivity reactions occur when the immune system mounts an excessive or
inappropriate response to an antigen, resulting in tissue damage. These reactions
are classified into four types based on the underlying immune mechanisms.
Type I (Immediate Hypersensitivity) is mediated by immunoglobulin E (IgE).
Upon exposure to an allergen, IgE binds to mast cells and basophils, causing the
release of histamine and other inflammatory mediators. This leads to vasodilation,
bronchoconstriction, and increased vascular permeability.
Type II (Cytotoxic Hypersensitivity) involves immunoglobulin G (IgG) or
immunoglobulin M (IgM) antibodies binding to cell surface antigens, leading to
complement activation and cell destruction.
Type III (Immune Complex Hypersensitivity) occurs when antigen–antibody
complexes deposit in tissues, triggering inflammation and tissue injury through
complement activation.
