Hives, also known as urticaria, are raised, itchy welts on the skin that can appear suddenly. They can vary in size and shape and are often red or skin-colored. Hives can be triggered by various factors, including allergies to foods, medications, or insect stings. Stress and temperature changes can also cause hives to develop. Most hives are temporary and may go away on their own within a few hours or days. Over-the-counter antihistamines can help relieve the itching and discomfort. If hives persist or are accompanied by other symptoms, it's important to consult a healthcare professional for further evaluation and treatment.