A Family Affair

The first thing you'll want to figure out is your family's allergy history. "The more people in your family who have allergies, the greater the risk your child will have one," says Dr. Sicherer.

Kathleen Murray-Lyons, of Townsend, Delaware, has allergies and asthma, so her pediatrician suggested special measures to decrease her 1-year-old son James's chances of food allergies. He recommended she delay introducing James to certain foods that are common allergens, such as nuts and eggs, and offer even low-allergenic foods, like carrots and rice, only gradually and one at a time (What to Introduce When). "So far, so good," says Murray-Lyons.

Another tactic doctors recommend: Wait to introduce any solids to your baby until after 6 months (as opposed to 4 months), since studies have found that this significantly decreases the risk of your child developing food allergies. As for what you should eat if you're breastfeeding, studies are mixed as to whether it's helpful to eliminate allergenic foods from your diet. Talk to your doctor about your particular case.

How to Recognize and Respond

Figuring out that your child has a food allergy can be half the battle. Leslie Norman-Harris of Woolwich Township, New Jersey, recalls the night her daughter, Camryn, 4, ate a mouthful of rice with shrimp.

"When she told us her mouth felt itchy, my husband and I looked ateach other and said, 'Uh-oh.'" Fortunately the symptoms subsided, but they knew not to give Camryn any more shrimp.

Other symptoms (which almost always appear a few minutes after eating the offending food) :

• Nausea
• Vomiting
• Diarrhea
• Itching (throat, mouth, eyes, skin, and/or ears)
• Lip swelling" "Rash (hives or a flare-up of eczema)
• Throat tightness (trouble swallowing or breathing)
• Tongue swelling that obstructs the mouth
• Chest pain
• Dizziness
• Sudden paleness or blueness, unconsciousness, and/or a faint pulse

For a mild allergic reaction, such as stomach upset or a rash, watch your child carefully in case she gets worse, and call your doctor. Torelieve discomfort, you can give her a weight-appropriate dose of an antihistamine such as Benadryl or its generic equivalent (diphenhydramine).

If your child has a severe allergic reaction (like throat tightness, lip swelling, or unconsciousness), call 911. She may need an injection of epinephrine. Later, talk with your doctor about whether you should keep epinephrine on hand.