6 Things You Need to Know About Food Allergies

By Dr. Samreen Hasan

What if getting lunch with a friend could be deadly? That's a real possibility for someone with a serious food allergy.

Every year, up to 200 people with food allergies die from anaphylaxis, a severe allergic reaction characterized by a variety of symptoms including shortness of breath, low blood pressure and vomiting and swelling. About 1 percent of the overall population, including 8 percent of children, lives with food allergies, and the prevalence is on the rise.

Given the growing concern about food allergies, Dr. Richard Besser, ABC News' chief health and medical correspondent, hosted a twitter chat to help educate others on the topic. Participants included major expert organizations such as Food Allergy Research & Education, the American Dietetic Association, and the Asthma and Allergy Foundation of America, as well as people living with food allergies and top hospitals from across the country.

For a full transcript of the chat, click here. Read on for an overview of the six main topics main covered in the chat.

What is a food allergy? A food allergy is the immune system's overreaction to a protein found in a particular food. Symptoms can occur with exposure to even a tiny amount of the allergen. Food allergies differ from food intolerances, which are food sensitivity. For instance, lactose intolerance is sensitivity to sugars in dairy that causes gastrointestinal distress, but is not an allergic reaction to dairy proteins. Eight foods are responsible for the majority of food allergies: cow's milk, eggs, fish, peanuts, shellfish, soy, tree nuts and wheat.

Who gets food allergies? Many food allergies are diagnosed in young children, but can also appear in older children and adults. Some children outgrow their allergies as they get older. More than 40 percent of cow's milk allergies resolve by the time a child is 8, but with other foods, such as peanuts and shellfish, the allergy tends to persist for a lifetime.

What are the symptoms of food allergies? An allergic reaction normally occurs within minutes of eating the trigger food. Symptoms include hives, red, itchy skin, and itchy nose and eyes, as well as vomiting, stomach cramps or diarrhea. The most severe reaction, anaphylaxis, is life threatening.

How do I know if I have a food allergy? If you have any of the above symptoms after eating, you should visit an allergist to determine whether you have a food allergy. The allergist might perform a skin test by scratching or pricking your skin with food extract. Alternatively, the allergist might do blood tests looking for specific antibodies the body produces to combat an allergen. The most reliable test is a food challenge, where the allergists observe your eating a small quantity of food in their office. Never attempt one of these on your own.

How can food allergies be prevented? Data shows that breast-feeding for the first four to six months of a child's life might prevent food allergies. Other methods of prevention are still under study.

Once you are diagnosed with an allergy, there are several ways to prevent symptoms. Avoiding the trigger food is the most reliable way to head off a reaction. Reading food labels is also a good idea. When eating out, always tell the server or chef about your allergy. Carry an auto-injector filled with epinephrine in case of anaphylaxis. Remind your loved ones that even a nutty kiss can be dangerous for you.

What is it like living with a food allergy? Individuals with food allergies and parents of allergic children live in constant fear of allergic reactions. Everyday activities such as cooking, grocery shopping, and eating out must be done with vigilance. Traveling can be a challenge. Parents often worry about leaving their child with allergies at school, daycare or with a babysitter. What's more, children with food allergies can be subject to bullying. But you can overcome these challenges. Our experts recommended focusing on enjoying what you can eat rather than dwelling on what you can't.