Hypersensitivity vs. Allergy — What's the Difference?

Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune system and these reactions may be damaging and uncomfortable.

Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis.

Highly or excessively sensitive.

A condition in which exposure to a substance, such as pollen, latex, animal dander, or a particular food or drug, causes an overreaction by the immune system that results in symptoms such as sneezing, itching, rash, and difficulty breathing or swallowing.

Responding excessively to the stimulus of a foreign agent, such as an allergen.

(Informal) An adverse sentiment; antipathy

Any heightened immune response to an antigen; an allergy; hypersensation.

A disorder of the immune system causing adverse reactions to substances (allergens) not harmful to most and marked by the body's production of histamines and associated with atopy, anaphylaxis, and asthma.

The state of being easily offended or hurt.

(pathology) Any condition of hypersensitivity to a substance.

Pathological sensitivity

Altered susceptibility to a first treatment as exhibited in reaction to a subsequent one.

Extreme sensitivity

(informal) An antipathy, as toward a person or activity.

Hypersensitivity to a particular substance.

Hypersensitivity reaction to a particular allergen; symptoms can vary greatly in intensity