An excessive, inappropriate, or harmful immune response to a substance or stimulus.
Hypersensitivity occurs when an immune response causes tissue injury or other harmful effects rather than providing only protective benefits. Hypersensitivity reactions are commonly classified into several types based on the immune mechanisms involved.
Allergic reactions are a form of hypersensitivity, but not every hypersensitivity reaction is an allergy. Autoimmune reactions and some reactions to medicines or other substances can also involve hypersensitivity mechanisms.
COMMONLY CONFUSED WITH
- Allergy: an immune-mediated hypersensitivity reaction to an otherwise harmless substance, typically involving a specific immune mechanism.
- Immune response: the broader term for the body’s response to an antigen or other stimulus; an immune response can be protective, harmful, or neutral.
SEE ALSO
- Allergy
- Anaphylaxis
- Immune Response
- Autoimmune
- Inflammation