Hives
Raised, red blotchy welts of various sizes that can appear and disappear randomly on the surface of the skin. This reaction is known medically as urticaria (from the Latin word urtica for “nettle”).
About one in five children experiences hives at some point in their lives, which are physically uncomfortable but generally harmless. Eventually, hives will disappear on their own without leaving any marks or scars.
Cause
While the cause of the reaction is often unknown, hives appear when a child is exposed to a trigger, prompting certain cells in the body to release histamine, a chemical released during allergic reactions. Hives appear when histamine causes blood plasma to leak from the small blood vessels under the skin.
A wide variety of triggers have been known to cause hives, including food, pollen, animal dander, drugs, insect bites, infections, illness, cold, heat, light, or stress. Foods that have been linked with hives include shellfish, fish, berries, nuts, eggs, and milk. Penicillin and aspirin are two types of drugs that may also trigger hives in susceptible patients.
In rare cases, hives can swell significantly and affect deeper layers of the skin and other parts of the body. This condition is called angioedema. In some children, there may be a genetic component to the angioedema. Termed “hereditary angioedema,” this condition is characterized by nonitchy swellings lasting three or four days that may be triggered by trauma or may appear spontaneously. With angioedema, the hands, feet, eyelids, lips, and even breathing passages can swell. Treatment for these is the same as for common hives.
Diagnosis
The pediatrician may be able to determine the cause of hives with a detailed medical history, including a detailed diary of exposure to foods, chemicals, new products, and possible irritants over a period of two weeks to a month before onset. However, because hives may be triggered by such a wide variety of irritants, it may never be possible to find out the exact cause.
Treatment
In many cases, hives will disappear or fade away on their own without any treatment. More persistent cases will respond to antihistamines, but other drugs also may be prescribed by the pediatrician, including adrenaline or epinephrine, terbutaline, oral corticosteroids, or cimetidine.
