A: Although you can be allergic to virtually any food, most allergies stem from a small number of sources. In children, the most common problem foods are egg, milk, peanut, soy, wheat, tree nuts (such as walnuts, pecans, almonds, cashews, and pistachios), fish and shellfish. Adults are most likely to run into problems with peanuts, tree nuts, fish and shellfish. Lately, we have seen an increase in allergies to seeds like sesame, poppy, and mustard, and to various fresh or raw fruits and vegetables, though reactions to the latter two are usually mild.

A: You are probably familiar with sudden severe food allergic reactions such as anaphylaxis. However, food allergies can also cause chronic illnesses such as digestive problems and skin rashes, known as atopic dermatitis or eczema.

A: Also called eczema, atopic dermatitis is a chronic skin disease estimated to occur in 15 percent of children. About one in three children with moderate to severe atopic dermatitis has some food allergy. In infants and young children, atopic dermatitis is often the first sign that a child is prone to allergies and may develop food allergies, asthma, or nasal and eye reactions to airborne substances such as pollens and animal dander.

People with eczema have dry skin and an itchy, red rash. It’s very difficult not to scratch, and the scratching itself contributes to eczema flare-ups and can lead to bacterial or viral skin infections, which then cause even more itching, redness, and inflammation. Although eczema can be uncomfortable, it is not generally dangerous if you get appropriate treatment to clear up the skin lesions. Unfortunately, there’s no treatment that cures eczema permanently. Even if you’ve had all of your food allergies diagnosed and avoid each one, your eczema will come and go. Many non-food triggers can cause eczema flares, including stress, fever or viral illness, sweating, weather changes, and irritating clothing. The good news is that eczema usually improves with age.

A. Our allergists take a medical history and perform a physical examination to determine whether your problem is related to foods or other allergic triggers. You may need further testing, such as an allergy skin prick test or blood test measuring IgE antibodies to specific allergens. Another possibility is an oral food challenge, where you eat a little bit of the food that’s a concern, under medical supervision, to determine if you can tolerate it.

A. Once you or your child has been diagnosed with a food allergy, we explain how to avoid the problematic foods and how to recognize and treat a reaction. Our researchers are trying to develop better treatments and discover cures for food allergies.

A. Some food allergies, such as egg, milk, wheat, and soy, often resolve in childhood. But others, including peanuts, tree nuts, fish and shellfish allergies, usually persist, though people have been known to outgrow them. About 20 percent of young children eventually grow out of their peanut allergies, while about 10 percent outgrow allergies to tree nuts.

A. We recommend breastfeeding for infants. There is no evidence to suggest that delaying introduction of allergens such as egg, milk, or peanut in otherwise healthy infants who are developmentally ready is problematic.   A study showed that early introduction of peanuts to infants who show signs of allergies but are not already allergic, in forms that are not choking hazards, have reduced the risk of peanut allergy.  Recommendations about infant diet change often, so ask your allergist for the latest advice.

A. Food allergies affect each individual and family differently. You should always take the possibility of anaphylaxis seriously, though it is both preventable and treatable. We provide the education and tools you need to make informed decisions and manage your child’s food allergies. In general, try to keep your life and activities as normal as possible. It should not be necessary to avoid social events, travel, or school.