Hypersensitivity

**Semantic type:** Disease or Syndrome

**Definition:** An immune response that occurs following exposure to an innocuous antigen, but that does not require the presence of preformed antibodies to the antigen.

**Synonyms:** - Allergic reaction - Hypersensitive - Hypersensitivity Reaction - Hypersensitivity Reaction - Hypersensitivity/Allergic reaction - Sensitive - Sensitivity - hypersensitivity