PATHOLOGY

Detailed explanation-1: -First, it sends a chemical signal to “mast cells” in your skin, lungs, nose, mouth, gut, and blood. The message is, “Release histamines, ‘’ which are stored in the mast cells. When they leave the mast cells, histamines boost blood flow in the area of your body the allergen affected.

Detailed explanation-2: -Histamine is released from cells in response to an antibody called immunoglobulin E (IgE). This antibody may be secreted in response to an invading pathogen such as a virus, bacteria, or an allergenic substance such as pollen. Histamine can also be released in response to injury caused by toxins.

Detailed explanation-3: -Histamine released by mast cells activated by allergen in the skin causes large, itchy, red swellings of the skin.

Detailed explanation-4: -In an allergic reaction-the immune system’s hypersensitivity reaction to usually harmless foreign substances (called antigens in this context) that enter the body-mast cells release histamine in inordinate amounts.