Urticaria presents as red itchy lesions over the skin that are raised over rest of the skin area. They occur in various shapes and sizes. Urticaria can occur anywhere on the body. It is very common disease and cause often is unknown. It resolves by itself and is rarely life-threatening. Angioedema can spread rapidly leading to skin rash and swelling. If it involves the throat it may lead to difficulty in breathing and can be life threatening.