Hives, known in the medical world as urticaria, are your skin’s reaction to histamine (a chemical released by the body’s immune system in response to an allergen) and other inflammatory signals being released into your bloodstream. (1)
RELATED: What Is Histamine?
You likely know hives for the way they appear on your skin: They’re red, swollen welts that can sometimes be accompanied by itchiness or pain. There are a variety of possible causes for hives (or reasons that histamine and other chemicals get released by the body in the first place). They could be the result of allergies in response to foods, medication, or an infection, or they could be from another trigger, like exercise, heat, stress, or alcohol. (2,3)
Red bumps on the skin can seem like a somewhat generic description. Couldn’t that indicate a number of possible skin issues? How can you know if it’s hives you’re experiencing and not something else? Here’s what to know about hives and their unique symptoms.
“Hives are characterized by red or pale-colored welts on the skin, which typically come and go throughout the day,” says Sourab Choudhury, DO, a dermatologist and the chief medical officer at the Dermatology Specialists, a private dermatology practice in New York City. “Sometimes they itch, burn, or sting.”Usually the welts will be surrounded by clear edges. They may look similar to bug bites, but hives generally will appear and disappear more quickly. They may itch, sometimes severely, and they’re not always the same size or shape. They may be as small as the tip of a pen or as large as a dinner plate. (4) When you press the center of a hive bump on the skin, it likely will turn from red to white, which is known as blanching. (2,3)
Hives may appear on the body grouped together and take over a large area of the skin, or as a couple of individual welts that show up here and there. (4) They can appear anywhere on the body, though some people get them in the same spot over and over again (usually as a result of a specific trigger). (4)
Generally, you’ll know you have hives simply by seeing the hives themselves. If you experience other symptoms, such as swelling in the eyes, lips, or inside of the throat, or if you have trouble breathing, you should call 911 or see a doctor immediately, says Sapna Palep, MD, a dermatologist at Spring Street Dermatology in New York City. These symptoms indicate you may be experiencing a serious allergic reaction called anaphylaxis. (5)
How to Know It’s Hives and Not One of These Other Skin Problems
“To the untrained eye, hives can have a similar appearance to other common skin conditions,” Dr. Choudhury says. He says one way to tell the difference is by how quickly the welts clear up.
