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.
About half these cases are associated with some immune findings. Chronic hives may also be associated with thyroid disease, other hormonal problems or, in very rare instances, cancer. Even this condition usually dissipates over time. Physical urticaria. In physical urticaria, the hives have a physical cause, such as exposure to heat, cold or pressure. Common triggers include: Rubbing or scratching (simple dermographism). This is the most frequent cause of physical urticaria. Symptoms appear within a few minutes in the place that was rubbed or scratched and typically last less than an hour.