PATHOLOGY

Detailed explanation-1: -Mast cells release histamine as well as other vasoactive molecules, which cause urticaria (hives). If the antigen activates mast cells in deeper tissue, this can lead to angioedema. If the response is prolonged, atopic dermatitis or eczema may occur.

Detailed explanation-2: -Mast cells are now thought to exert critical proinflammatory functions, as well as potential immunoregulatory roles, in various immune disorders through the release of mediators such as histamine, leukotrienes, cytokines chemokines, and neutral proteases (chymase and tryptase).

Detailed explanation-3: -Histamine released from mast cells and basophils exerts its biological activities by activating four G protein-coupled receptors, namely H1R, H2R, H3R (expressed mainly in the brain), and the recently identified H4R.

Detailed explanation-4: -Too many mast cells are produced and build up in tissues and body organs, releasing substances such as histamine, leukotrienes and cytokines that cause inflammation and symptoms.

Detailed explanation-5: -The granules of mast cells are loaded with histamines. Histamines increase the blood flow to the area and the leakage of fluid and proteins from the blood into the tissue space. Thus, the quick release of histamine produces the redness and swelling associated with inflammation.