I have chronic hives but no allergies have been identified. Are hives always caused by allergy?
 
 

No. Urticaria is the medical term for hives which are red whelps and itchy areas of the skin that are swollen. Urticaria is often associated with swelling of the lips, tongue, hands, or feet. They can appear on any location of the body and come in a variety of sizes. Acute hives last from hours to days, while chronic hives last for over 6 weeks. 

There are a number of possible allergic triggers including foods, medications, latex, and occasionally other inhalants. 

Over-the-counter aspirin (Bayer®) or aspirin-like products such as Motrin®, Aleve®, Advil®, etc.,) can cause or make hives worse. 

All hives are not caused by allergy. Non-allergic causes of hives include infections, other chronic medical conditions (for example, lupus, some cancers, thyroid disease), or exercise. 

Physical hives can be caused by exposure to heat, cold, friction or pressure applied to the skin, or water. Skin testing can often identify the cause.