Urticaria, or hives, is a common skin condition marked by raised, red, and itchy welts that vary in size and may appear in clusters on the face, arms, legs, or trunk. These welts are usually temporary, disappearing within hours or days, but can sometimes recur and disrupt daily life.

The welts “can be little patches or huge plaques,” and are often very itchy. Despite how alarming they may look, urticaria is usually harmless. It’s caused by the release of histamine and other chemicals from mast cells, leading to swelling as fluid leaks from tiny blood vessels in the skin.

In some cases, urticaria is accompanied by **angioedema**, a deeper swelling that commonly affects the hands, feet, lips, eyelids, or genitals. This can feel painful or tight. If angioedema affects the tongue or throat, it becomes a **medical emergency** due to breathing risks.

The most frequent form is **acute urticaria**, which “typically lasts less than six weeks” and often has a known trigger, such as food, medication, or infection.

While usually temporary, urticaria can be physically uncomfortable and emotionally distressing, especially when chronic or severe.