Hives — also called urticaria — are itchy, raised welts that appear on the skin. On lighter skin they often look pink, red, or flesh-colored, while on brown or Black skin they may appear slightly lighter, darker, or the same tone as the surrounding skin. They can sometimes sting or feel painful, but in most cases they are linked to an allergic reaction or temporary irritation.

Hives usually develop when the immune system reacts to a trigger such as food, medication, insect bites, or environmental allergens. In response, the body releases histamine, a chemical that causes itching, swelling, and redness. However, hives are not always allergy-related. Stress, infections, exercise, tight clothing, heat, cold, or sweating can also trigger them, and sometimes the exact cause is never identified.

People with known allergies are more likely to experience hives, especially if they are exposed to common triggers like pollen, certain foods, animal dander, or medications. Symptoms can include clusters of raised welts that change shape or location, intense itching, and in some cases swelling around the eyes, lips, or face. Chronic hives last more than six weeks and may come and go repeatedly over time.

Most mild cases improve with antihistamines and simple home care such as cool baths, avoiding scratching, and staying away from heat. However, medical attention is important if hives persist, worsen, or appear alongside symptoms like dizziness, breathing difficulty, or swelling of the throat — which may indicate a severe allergic reaction requiring emergency care.