Chapter 45.6, Problem 4C

Summary Introduction

To draw: The sequence of immunological events that takes place in a common type of allergic reaction, such as a hay fever.

Introduction: Overreaction of the immune system toward the normally harmless substances is known as allergic reaction. The causative agent or any substance that causes allergy is called an allergen. The common allergen includes chemical, drug, food or pollen from the plant. Re-exposure of the same allergen immediately stimulates the IgE to bind to the sensitized mast cells and releases the chemical mediators, such as histamines from the mast cell granule to cause allergic reactions.