What is hypersensitivity? allergies? autoimmune disorders?

Hypersensitivity is also known as  intolerance which is defines as an unwanted reactions due to changes or interference with immune system for example  allergies and autoimmunity. Hypersensitivity is the reaction of immune system that can be harmful and weakens once body.

Allergy is kind of hypersensitive reaction which is having fast response within few minutes rather than hours or days. In the case of allergies free antigens cross link with IgE on mast cells and basophils and releases vasoactive biomolecules. Few example of Allergies are anaphylaxis and asthma.

Autoimmune disorders are also a kind of hypersensitive reaction which occurs when body's immune system attacks own body cells mistakenly. few examples are Type 1 diabetes, Rheumatoid arthritis (RA), and Multiple sclerosis.