A 35-year-old woman is concerned that she may be allergic to certain foods. She gets a rash several hours after eating small amounts of peanuts. In evaluating the possibility of food allergies,
which of the following is correct?A) At least 30% of the adult population is allergic to some food substance
Food allergy is an IgE-mediated reaction to antigens in food. It is caused by glycoproteins found in shellfish, peanuts, eggs, milk, nuts, and soybeans. Symptoms occur within minutes (not hours) of ingestion in most patients. The incidence of true food allergy in the general population is uncertain but is likely to be about 1% of patients—less than might be generally perceived. Studies have demonstrated that breastfeeding can decrease the incidence of allergies to food in infants genetically predisposed to developing them. Food allergy symptoms most commonly affect the gastrointestinal tract (cramping, diarrhea) and the skin (urticaria). Respiratory and (in severe reactions) cardiovascular symptoms are rare. Food allergic reactions are diagnosed by the medical history, skin or radioallergosorbent tests (RASTs), and elimination diets. The best test, however, remains the double-blind, placebo-controlled food challenge. If the diagnosis of a food allergy is confirmed, the only proven therapy is avoidance of the offending food. At present, there is no proven role for immunotherapy in the treatment of food allergy.