Many children develop hives, which are swollen, red welts that, by definition, are quite itchy. Oftentimes the itching starts before the welts appear.
Hives are a very common problem and it is estimated to affect at least 20 percent of people some time during their life. The medical term for hives is urticaria.
There are two types of urticaria:
- Acute urticaria are hives that last six weeks or less
- Chronic urticaria happens when hives last or recur for more than six weeks
Acute urticaria in a child can be caused by infections, foods, medications, insect bites or blood transfusions. When a child develops acute hives, the first thing that usually comes to mind is, “What did she or he eat that caused this rash?” However, most cases of childhood hives are a result of infections. Some infections that can cause hives in children include respiratory viruses (common cold), strep throat, urinary tract infections, hepatitis, infectious mononucleosis (mono) and many other viral infections.
In an infant or a toddler who is being introduced to new foods, think about food allergy as a possible cause of the hives, especially peanuts, tree nuts, eggs, cow’s milk, and fish or shellfish. If your child develops hives while or shortly after playing outdoors, look at their skin for any signs of insect bites, especially fire ants in our area. When a child develops hives while taking a medication, the hives could have been caused by the medication, but this gets tricky if the child is taking an antibiotic, since the hives could also have been caused by the initial infection for which she was taking that antibiotic.
A single episode of hives in an otherwise healthy child does not usually need extensive testing, as most of the time it is caused by a viral infection. However, if hives reoccur, you should see your pediatrician or an allergy specialist to evaluate possible causes. Once the cause of hives is identified, the best treatment is to avoid or eliminate that cause (in the case of foods, medications with the help of a physician, insects). For hives caused by infections, they may take up to three weeks to resolve, but antihistamines will usually help improve the hives until completely resolved.
Chronic hives are often a challenge for the child, parents and physician. In many cases, we cannot identify the cause of chronic hives, and this is called idiopathic urticaria, or chronic autoimmune urticaria, when the immune system is suspected to be the root cause of the hives. Chronic hives can also be caused by thyroid disease, other endocrine problems or, very rarely in children, cancer. There is a type of chronic hives called physical urticaria, in which hives are caused by rubbing or scratching the skin (dermatographism), constant pressure (pressure urticaria), by changes in temperature (heat or cold urticaria), or sun exposure (solar urticaria). Chronic hives should be evaluated by an allergist who will take a very detailed history and may perform some testing (blood, urine or skin tests). Chronic hives are frequently treated by a combination of two or three antihistamines, and in more severe cases, short courses of steroid medications or long-term immune modulators. If hives involve swelling of tongue or lips, or are accompanied by trouble breathing, your child may be prescribed an epinephrine autoinjector to use in case of emergency.
The good news is that in most cases of chronic hives, they gradually disappear over time. For some children, they disappear in a few months, but in others they may continue to recur for several years. In these cases, it is more effective to take the medications daily than to wait for breakouts.