Hives — also known as urticaria — are raised, red, itchy welts (wheals, or swellings) of various sizes that seem to appear and disappear on your skin. Angioedema, a type of swelling, causes large welts deeper in your skin, especially near your eyes and lips.
In most cases, hives and angioedema are harmless and don't leave any lasting marks, even without treatment. The most common treatment for hives and angioedema is antihistamine medications. Serious angioedema can be life-threatening if swelling causes your throat or tongue to block your airway and leads to loss of consciousness.