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 hista-mine, 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 angio-edema," this condition is characterized by non-itchy swellings lasting three or four days that may be triggered by trauma or may appear spontaneously. With angioedema, the hands, feet, eye lids, lips, and even breathing passages can swell. Treatment for these is the same as for common hives.
Was this article helpful?