Urticaria, commonly known as hives, is a skin condition characterized by raised, itchy welts or bumps. These welts can vary in size and may appear anywhere on the body. Urticaria occurs when the body releases histamine and other chemicals in response to allergens, stress, or certain medications, leading to inflammation and swelling. The condition can be acute, lasting less than six weeks, or chronic, persisting for months or even years. Common triggers include pollen, pet dander, certain foods, and insect stings. Treatment often involves antihistamines to relieve itching and reduce swelling.