Complications of hives and angioedema may include:

  • Itching. Hives and angioedema can cause itching and discomfort.
  • Difficulty breathing. In more-serious cases — when swelling occurs inside your mouth or throat — complications can include difficulty breathing, leading to a loss of consciousness. If you have a swollen throat, seek medical care immediately.
  • Anaphylactic shock (anaphylaxis). This is a serious allergic reaction involving your heart or lungs that can also be associated with hives and angioedema. Your bronchial tubes narrow, it's difficult to breathe, and your blood pressure drops, causing dizziness and perhaps loss of consciousness or even death. Anaphylactic shock occurs rapidly and requires immediate medical care.
Sep. 17, 2011