What Are Hives?

Learn about the triggers, symptoms, and treatments

What Do Hives Look Like on a Baby?

    child with hives rash iStockphoto

    There's nothing fun about a kid with hives. And if you're reading this, that kid is probably yours. You're wondering what's causing them, how to treat them, and if there's any way to prevent them. Read on. We've compiled a guide to all things hives.

    Simply put, hives are a red rash that's starting to itch. The red spots, also called welts, can cover either a small or large portion of body. They could be as small as a pinpoint or as large as a dinner plate. In the case of the larger welts, the red areas have joined together to form even larger patches called plaques.

    If there are any suspicions of possible allergic triggers, a blood test will be done to look for antibodies that have been formed in response to antigens that have entered the body and caused the immune system to react by releasing histamine. "Histamine causes the walls of the blood vessels to leak plasma to the surrounding tissues," explains Brandi M. Kenner-Bell, M.D., F.A.A.D., F.A.A.P., assistant professor of pediatrics and dermatology at Northwestern University's Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago. "The result is hives on the surface of the skin."

    Hives are usually categorized as acute or chronic. Acute hives are common in kids and are most likely caused by an allergic reaction. Chronic hives (lasting more than six weeks) are much more of a mystery, but they're also very rare in children.

      What Triggers Hives?

      In adults, hives can be caused by something other than an allergy, such as illnesses, infections, exercise, and exposure to the sun. Hives in kids are almost always an allergic reaction, says Jon McCullers, M.D., pediatrician-in-chief at Le Bonheur Children's Hospital in Memphis. These are the common triggers:

      1.) Medication, food, or pollen and pet irritants.

      2.) Insect bites or stings, specifically from bees, yellow jackets, mosquitoes, chiggers, and fleas.

      3.) Poison ivy, metals from jewelry, and lotions and soaps.

      "We hardly ever see hives with small infants because allergic reactions are triggered by the immune system," explains Dr. McCullers. "You need to have multiple exposures in order to have the allergy itself." By the time a child reaches about 2, she will either have built up a tolerance for something or developed an allergy to it. "Immune systems become more mature, and capable of a reaction, the older a child gets," says Dr. McCullers.

        Symptoms of Hives

        Hives can start to appear within minutes or a couple of hours of exposure; within a day, the rash could already be gone. Sometimes as the rash begins to fade, new hives appear, extending the bout for several days.

        Hives can be either generalized (appearing all over the body) or local (limited to one spot). The good news is that your kid can't spread the rash by scratching it. "A child can aggravate it locally, causing more histamine to be released in that particular area," says Dr. McCullers. "But he can't move it around. If hives spread all over the body, that's just the course of the rash."

        Angioedema, a swelling beneath the skin, is not a symptom of hives, but it can accompany them and often causes the eyelids and lips to swell. Extreme swelling from angioedema could block the airways. If your child is having trouble breathing, take her to the emergency room immediately.

          How to Treat Hives

          Generally, parents can manage treatment from home with over-the-counter antihistamines such as Benadryl. "Antihistamines can make some children sleepy and others hyperactive," says Dr. McCullers. "If the side effects of a drug are too extreme, your doctor can recommend or prescribe another."

          Your goal is to ease the itch. A topical cortisone cream (.5 or 1 percent) can help, along with cold compresses applied to the affected areas.

          Kids experiencing angioedema with their hives might need an oral steroid or stronger antihistamine to get the swelling under control. If the swelling affects their ability to breathe, a shot of epinephrine might be used to rapidly reverse the allergic reaction.

          "In most cases, hives go away within 24 hours," says Dr. Kenner-Bell, especially hives that affect only a small part of the body. "Kids should be seen by their doctor if their hives are more severe," says Dr. McCullers. "If they're all over the body, are accompanied by uncontrollable itching or extreme swelling, or last for an extensive period of time, see your doctor."

            Preventing Hives

            The best course of action is to try to identify the trigger. "We start by asking what new things a child has been exposed to," explains Dr. McCullers. This could include a new food, a new soap, or a new piece of jewelry. "After that, we move on to allergy testing on the skin," he says. If you can find the allergen, there is a chance that your child will eventually build up a tolerance for it. "But for really severe reactions, we recommend lifelong avoidance," says Dr. McCullers. "You just can't risk the reaction by testing to see if it's gone away."

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