What Are Hives? Hives are pink or red bumps or slightly raised patches of skin. Sometimes, they have a pale center. Hives usually itch, but they also can burn or sting. Hives can happen anywhere on the body. They can be tiny or as big as a dinner plate. The spots also might look like rings or groups of rings joined together in clusters. Hives can change locations in a matter of hours. A bunch of hives might be on a person's face, then go away. Later, more may appear on the person's arms. Hives are common and usually harmless. But occasionally they're a sign of a serious allergic reaction. So, always tell your mom or dad if you get them. The medical term for hives is urticaria (say: ur-tuh-KAR-ee-uh). When a person is exposed to something that can trigger hives, certain cells in the body release histamine (say: HIS-tuh-meen) and other substances. This causes fluid to leak from the small blood vessels under the skin. When this fluid collects under the skin, it forms the blotches, which we call hives. Why Do I Get Hives? People can get hives for lots of different reasons (though sometimes, the cause is not known). One common reason for getting hives is an allergic reaction. Some common allergic triggers are certain foods (like milk, wheat, eggs, shellfish, berries, and nuts), medicines (such as antibiotics), and insect stings or bites. Other causes of hives are not related to allergies and these can include: exposure to the cold (like diving into a cold pool) exercise sun exposure nervousness or stress infections caused by viruses No matter what the cause, a case of hives can last for a few minutes, a few hours, or even days. What Will the Doctor Do? Doctors usually can diagnose hives just by looking at you and hearing your story about what happened. The doctor can try to help figure out what might be causing your hives, although often the cause will remain a mystery. If you're getting hives a lot, or your reaction was serious, your doctor might send you to another doctor who specializes in allergies. Sometimes, doctors will suggest you take a type of medicine called an antihistamine to relieve the itchiness. In many cases, hives clear up on their own without any medication or doctor visits. Less often, hives can be a sign of a more serious allergic reaction that can affect breathing and other body functions. In these cases, the person needs immediate medical care. Some people who know they have serious allergies carry a special medicine to use in an emergency. This medicine, called epinephrine, is given by a shot. Usually, a nurse gives you a shot, but because some allergic reactions can happen really fast, many adults and kids carry this emergency shot with them and know how to use it, just in case they ever need it in a hurry. Can I Prevent Hives? Yes and no. The answer is "yes" if you know what causes your hive. If you know something causes you trouble, you can try to avoid it. If you get hives when you're nervous, relaxation breathing exercises may help. But if you don't know why you get hives, it's tough to prevent them. Some kids get hives when they have a virus, such as a bad cold or stomach flu. Other than washing your hands regularly, there's not much you can do to avoid getting sick occasionally. The good news is that hives usually aren't serious and you might even grow out of them. Who wouldn't want to give hives the heave-ho? Back to Articles Related Articles Learning About Allergies During an allergic reaction, your body's immune system goes into overdrive. Find out more in this article for kids. Read More How to Be Safe When You're in the Sun It's fun to be outside on a hot, sunny day. But too much sun and heat can make you feel terrible. Find out how to stay safe in this article for kids. Read More Food Allergies Struggling with strawberries? Petrified of peanuts? Sorry you ate shellfish? Maybe you have a food allergy. Find out more in this article for kids. Read More Nut and Peanut Allergy A growing number of kids are allergic to nuts and peanuts. Find out more about this problem and how allergic kids can stay healthy. Read More Egg Allergy Babies sometimes have an allergic reaction to eggs. If that happens, they can't eat eggs for a while. But the good news is that most kids outgrow this allergy by age 5. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.