Urticaria:

(also called hives.) - a condition in which red, itchy, and swollen areas appear on the skin - usually as an allergic reaction from eating certain foods or taking certain medications. 

Itchy, swollen, red bumps or patches on the skin that appear suddenly as a result of the body’s adverse reaction to certain allergens. They can appear anywhere on the body including the face, lips, tongue, throat or ears. Hives vary in size and can last for minutes or days. 

an itchy skin eruption characterized by weals with pale interiors and well-defined red margins; usually the result of an allergic response to insect bites or food or drugs