Chronic urticaria and angioedema are conditions marked by hives lasting more than six weeks. The cause of this type of hives is usually more difficult to identify than those causing acute urticaria. For most people with chronic urticaria, the cause is impossible to determine. In some cases, though, the cause may be thyroid disease, hepatitis, infection, or cancer.
Chronic urticaria and angioedema can affect other internal organs such as the lungs, muscles, and gastrointestinal tract. Symptoms include muscle soreness, shortness of breath, vomiting, and diarrhea.