constituting or forming a large number; numerous: many people. noting each one of a large number (usually followed by a or an): For many a day it rained. a large or considerable number of persons or things: A good many of the beggars were blind. the many, the greater part of humankind. many persons or things: Many of the beggars were blind.
Hives and angioedema can be caused by: 1  Foods. Many foods can trigger reactions in people with sensitivities. 2  Medications. Almost any medication may cause hives or angioedema. 3  Common allergens. Other substances that can cause hives and angioedema include pollen, animal dander, latex and insect stings.  Environmental factors.
Physical urticaria: Hives caused by direct physical stimulation of the skin -- for example, cold, heat, sun exposure, vibration, pressure, sweating, and exercise. The hives usually occur right where the skin was stimulated and rarely appear elsewhere. Most of the hives appear within one hour after exposure. Dermatographism: This is a common form of physical urticaria where hives form after firmly stroking or scratching the skin. These hives can also occur along with other forms of urticaria.