What are hives?
Hives, also known as urticaria or welts, are swollen areas on the skin. They usually itch. They can show up in different shapes and sizes, but are usually well defined, with a pale, central, raised area surrounded by a red border.
© Dr P. Marazzi / Photo Researchers, Inc
Hives are common, but not contagious. They typically last for a few hours to a few days, but it's possible to have them for months at a time.
Hives may disappear from one area of your child's skin – only to crop up elsewhere.
What causes hives?
Hives occur when the body releases a chemical called histamine. There are so many possible reasons for hives that you may have trouble identifying the culprit. Here are the most likely ones:
- Insect bites and stings. If your child is allergic to bees or fire ants, for example, he may develop hives in reaction to being stung or bitten.
- Food. Your child might get hives in reaction to something he eats. The most likely foods to offend are milk, eggs, peanuts, tree nuts (e.g., almonds, walnuts, pecans), soybeans, wheat, fish, and shellfish. Certain food additives and preservatives can also trigger hives. Your child may break out in hives because he's allergic to the protein in the food, or simply because his body reacts to a chemical in the food by releasing histamine. Some children even develop hives simply from coming into contact with certain foods – for example, when the juice from a strawberry gets on their skin.
- Allergens. Children who have developed an allergy to cats may break out in hives when they touch a cat. Your child may even react with hives to an allergen in the air, like pollen.
- Illness. Your child might get hives when he has a cold or other viral infection. Less commonly, he may get hives when he has a bacterial infection.
- Temperature. Sometimes cold temperatures cause hives. The same goes for a sudden change in temperature – when your child's skin warms up quickly after being cold, for example.
- Drugs. Antibiotics and some other medications might cause your child to break out in hives.
How should I treat hives?
If you think your child has broken out in hives because of a pet or pollen allergy, give him a bath to rinse away as much of the allergen as possible. Cool compresses – and cool baths – sometimes provide relief. You might also try dabbing the hives with calamine lotion on a cotton ball.
Avoid dressing your child in clothing that's snug in the area where he has hives.
If hives are making your child uncomfortable, ask his doctor whether you can give him the appropriate dose of an oral antihistamine to reduce itching and swelling.
When should I call the doctor?
Call 911 immediately if your child has respiratory symptoms such as wheezing or shortness of breath, if his face or tongue swells, or if he passes out. Along with hives, these symptoms can signal anaphylactic shock, a potentially fatal allergic reaction. A baby's respiratory system is so tiny that even a small amount of swelling can make it very difficult for him to breathe.
If you've given your child an oral antihistamine and he's still not comfortable, or if it seems to make him too sleepy, call and ask the doctor about other options. Occasionally doctors will prescribe steroids, such as prednisone, to treat hives that don't respond to antihistamines.
Even if your child isn't troubled by the hives, talk with his doctor if they last more than a week.