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Health Tips for Parents

2006 Issues

How do I know if my child has a food allergy?

While many children who experience food allergies develop symptoms early in life, others develop sensitivities to certain foods as they reach school age or even later. The onset of a food allergy can be sudden, and symptoms vary. Once an allergy is identified, avoiding the food becomes critical, although some children will outgrow their allergies.

A food allergy develops when the body’s immune system reacts with an antigen, or foreign substance, in a particular food. The body produces a protein that reacts with the antigen to release histamine, which causes adverse reactions in the digestive or respiratory systems, or on the skin. An allergic reaction can be as mild as an upset stomach or rash — or as severe as gastrointestinal pain, labored breathing and, in some cases, anaphylactic shock or death, explains Maria Garcia-Lloret, M.D., UCLA pediatric allergist and immunologist at Mattel Children’s Hospital at UCLA, and co-director of UCLA’s Food Allergy Clinic.

While any food can be the source of an allergic reaction, according to Dr. Garcia-Lloret, 90 percent of all food allergies are caused by peanuts, eggs, milk, shellfish, wheat, tree nuts, soy and fish.

Signs and Symptoms
Allergic reactions to food may manifest in children as hives, which is an itchy rash that appears within minutes of eating a particular food. Lip and facial swelling may also occur.

Another common condition, especially in infants, is eczema, a chronic skin rash that can range from hot, dry itchy skin to more severe cases that leave skin bleeding and raw.

Food allergies may also cause indigestion, diarrhea or vomiting. “In some children, gastrointestinal problems or a general failure to thrive may be misdiagnosed as resulting from stress or poor diet,” Dr. Garcia- Lloret notes.

The most severe and potentially fatal allergic reaction — anaphylaxis — occurs when the body’s immune system reacts to otherwise harmless food proteins, resulting in constricted breathing, shock or death. For people with severe allergies, a doctor may recommend carrying epinephrine, a small dose of adrenaline, at all times.

In most cases, an allergist can diagnose food allergies using simple skin patch or blood tests. Physicians, along with a nurse and nutritionist, in UCLA’s Food Allergy Clinic provide testing and long-term monitoring to understand the condition and to help implement lifelong dietary changes.

Lifelong Monitoring
Many children grow out of their allergies by grade school, according to Dr. Garcia-Lloret. While the reasons for this remain unclear, one theory is that the immune system, which may not have been fully developed at birth, matures as the child grows. “Children who had a food allergy before 3 years old should retest in grade school,” Dr. Garcia-Lloret advises. “Some children follow restricted diets when, in fact, they are no longer allergic and can begin to enjoy foods that were once off-limits.”

On the other hand, children who never had allergies but begin to experience recurrent symptoms such as rashes or stomachaches may have developed a reaction to a certain food. “As children grow older, they are exposed to more and more antigens,” Dr. Garcia-Lloret explains. “Once in a while, the antigens may suddenly become confused, react with each other, and make the child react differently to a particular food.”

At present, the main treatment for food allergy is strict avoidance of the allergy-causing food to prevent an allergic reaction. Dr. Garcia-Lloret advises parents and children to ask questions about ingredients when eating out, and to read food labels carefully. She cautions, “Learn the ‘code’ words for certain ingredients, which may contain harmful derivatives of the food your child cannot eat.”

This information is provided courtesy of the pediatricians at the Mattel Children’s Hospital at UCLA. UCLA Healthcare pediatricians are conveniently located in your neighborhood. In addition to our Children’s Health Center in Westwood, we have offices in Brentwood, Culver City, Manhattan Beach, Santa Monica, and West Los Angeles. Additional information can be found on the UCLA Healthcare web site at www.healthcare.ucla.edu or by calling 1-800-UCLA-MD1 (1-800-825-2631).

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