Here's how to identify the rash and prevent it from coming back
child with hives rash
Credit: iStockphoto

Hives is a rash illness that can afflict anyone, including young kids. Unlike other rash-related illnesses, which can be accompanied by a fever, cough, or runny nose, hives target only the skin.

The appearance of hives can vary, depending on the child and the cause of the rash. Hives can be pale red or darker red and look like a series of small raised bumps, called welts. Sometimes the welts merge into larger plaques, says Brandi M. Kenner-Bell, M.D., assistant professor of pediatrics and dermatology at Northwestern University's Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago. These can vary drastically in size, some growing to the size of a dinner plate.

"If the hives stay in one area of the body, it usually means you have a specific trigger," says Dr. Kenner-Bell. "It's probably a reaction to something your child came in contact with." When you hear the term generalized, doctors are referring to hives that have spread all over the body. In that case, they're probably caused by a reaction to something that was inhaled or ingested.

Common Causes of Hives

When a small child gets hives, it's almost always due to an allergy. And a quick test of the skin, known as "wheal and flare," can help confirm that: If your child's skin has a big red patch and you see swelling (wheal) followed by a brighter redness (flare) when you drag a fingernail over it, it's an allergic reaction, explains Jon McCullers, M.D., pediatrician-in-chief at Le Bonheur Children's Hospital in Memphis.

Possible allergies to watch for include pollen or pet dander. A kid can take a big gulp of air, inhale either of these, and end up with hives. "The allergic response could also be a reaction to certain foods, medications, or insect bites or stings," says Dr. McCullers. Or it could be the result of a contact allergy: "New clothes, a new soap, or detergent could be the trigger," says Dr. McCullers. "Or a new piece of jewelry with a certain kind of metal." Poisonous plants could also be to blame. "Poison ivy shows up on the body as a form of hives," adds Dr. McCullers.

Treating Hives

Hives can usually be managed at home, as your main course of action is to try to alleviate the itch--and your child's urge to scratch. "Oral antihistamines are the easiest and safest way to treat hives that last up to six weeks," says Dr. Kenner-Bell. "I don't typically prescribe topical medicines for hives, but hydrocortisone may be helpful with the itch."

Hives can lead to angioedema, a condition in which fluid swells beneath the skin. This can become serious and affect a child's ability to breathe. "If a child's throat or tongue swells, if he's wheezing, or has difficulty breathing or tightness in the chest, parents should take him to the emergency room immediately," says Dr. Kenner-Bell. The child might need a shot of epinephrine to get the reaction under control.

Preventing a Reoccurrence of Hives

Unfortunately, you can't prevent hives if you don't know what's causing them. So the longer the symptoms last, the harder it is to pinpoint the culprit. You might be able to identify the trigger in hives, which are usually gone within 24 hours, because exposure was obviously very recent. But if they're acute (lasting up to six weeks) or chronic (lasting more than six weeks, which is extremely rare in young children), determining the trigger can prove more challenging.

The good news is that kids will outgrow some allergies. "By around age 2, your child will either have a tolerance for something or have developed an allergy to it," says Dr. McCullers. So if you have identified a trigger and the hives were fairly mild, you could introduce the allergen again to see if your child now has built up immunity. "But for really severe reactions, we recommend lifelong avoidance," says Dr. McCullers.

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