Chronic Urticaria Download PDF, 1.3MB, PDFWhat are Urticaria and Angioedema? Urticaria, also known as “hives”, occurs due to fluid leaking out from blood vessels in the skin. This causes swelling on the surface of the skin. Urticaria is characterized by red, itchy bumps on the skin’s surface. These may come in different shapes and sizes, appearing in certain parts of the body, or covering large areas of the body. The skin will return to its normal appearence in around 24 hours. Angioedema happens when swelling develops in the deeper layers of the skin. Swelling can happen around the eye, on the lips and tongue and even internally in the windpipe. This may last for about 48 to 72 hours. Urticaria and angioedema commonly occur together, but may also occur separately. [Please download the PDF file if you are unable to view the image below.]