When a susceptible person is exposed to an allergen, the body starts producing a large quantity of corresponding IgE antibodies. Subsequent exposure to the same allergen may result in an allergic reaction. Symptoms of an allergic reaction will vary depending on the type and amount of allergen encountered and the manner in which the body's immune system reacts to that allergen. Allergies can affect anyone, regardless of age, gender, race, or socioeconomic status. Generally, allergies are more common in children, however, a first-time occurrence can happen at any age, or recur after many years of remission.
Allergies tend to run in families.
Hormones, stress, smoke, perfume, or environmental irritants may also play a role in the development or severity of allergies. Anaphylactic shock, also called anaphylaxis, is a severe, life-threatening reaction to certain allergens. Body tissues may swell, including tissues in the throat. Anaphylactic shock is also characterized by a sudden drop in blood pressure. The following are the most common symptoms for analphylactic shock.