Urticaria

Urticaria, commonly known as “hives”, is a patchy redness of the skin that is itchy and may be slightly swollen; urticaria is often caused allergic reactions, autoimmune disorders, or other conditions, but sometimes the cause is unknown.

Urticaria refers to a group of conditions including itchy skin (pruritus), and patches of skin that are swollen, warm, mildly painful and itchy (angioedema).

Learn more

 * Urticaria - MSD Manuals
 * Wikipedia page