Denetta King, age 12, of Keen, N.H., for her question:

WHAT CAUSES HIVES?

Hives is an allergic disorder of the skin, characterized by sudden evanescent or repeated appearance of wheals, irregular, round skin lesions accompanied by inflammation and itching. The disease often appears in conjunction with hay fever or asthma and is attributed to an allergic reaction which occurs rapidly after ingestion, inhalation, injection or contact with an offending antigen.

Agents responsible for hives, technically known as urticaria, include many foods such as fish, shellfish, nuts and berries.