Understanding Food Allergy

Jan 01, 2016 Dr Zulfikar Bux

---

By Dr Zulfikar Bux

Assistant Professor of Emergency Medicine

Allergies to food are rapidly becoming a global challenge. According to the Centers for Disease Control and Prevention, food allergies among

children rose by fifty percent from 1997 to 2013. It is estimated that every three minutes someone has to visit an emergency department for food allergy. There is no clear cut evidence to explain this increase in food allergy, especially over the past two decades.

Today we will discuss this often ignored condition so that we can be better equipped to deal with food allergies.

 WHAT IS A FOOD ALLERGY?

A food allergy is a reaction by the body’s immune system to something in a food, usually a protein; the body mistakenly acts like it is a germ or some other invader, and does its best to defend itself.

While any food could possibly cause an allergy, certain foods are much more likely to do so. In children, the foods that most commonly cause allergic reactions are:

• Peanuts
• Eggs
• Milk
• Soy
• Wheat
• Shellfish
• Tree nuts

Most allergic reactions occur within 30 minutes of consuming the problem food. Often, the reaction occurs within 5 to 10 minutes, but it can occur as long as 4 to 6 hours after ingestion.

WHAT ARE SYMPTOMS OF FOOD ALLERGY?

It’s not always easy to know when someone has a food allergy, because there are many different symptoms. They include:

• Hives (a raised, pink, itchy rash)
• Scratchy throat
• Stomachache
• Nausea or vomiting
• Diarrhea
• Swelling, especially around the mouth and face
• Itchy eyes
• Nasal congestion/runny nose
• Other rashes, including eczema
• Wheezing, or just trouble breathing
• Difficulty with swallowing
• Rapid heart rate
• Lightheadedness
• In babies and small children, poor growth or blood in the stool

In severe cases, something called anaphylaxis can happen. This whole-body allergic reaction combines many of the symptoms mentioned above and can lead to death if not treated immediately.

HOW CAN FOOD ALLERGY BE DIAGNOSED?

Many times, the diagnosis of food allergy can be made by the history. For example, if a child has hives or swelling of the face after eating something with peanuts, they are likely allergic to peanuts. But because symptoms can be so varied, the diagnosis is sometimes harder to make. A detailed diary of food intake and symptoms and information about food allergies in the family can be helpful. But your doctor may need to do testing to be sure. There are two commonly used tests:

• Skin tests

The allergy skin-prick test is the most common screening test because it is inexpensive, easy to do, and generally reliable. It involves pricking the skin with a solution of the suspected food. A positive test will produce a small hive-like reaction.

• RAST blood tests

Radioallergosorbent (RAST) laboratory tests measure the amount of food-specific IgE in the blood. It basically is a test for antibodies that your body will produce in response to a food that it is allergic to.

ARE THERE ANY WAYS I CAN PREVENT FOOD ALLERGIES?

The following measures can help lower the risk that food allergies will develop in infants and young children:

• Don’t introduce solid foods until 6 months of age.
• If possible, provide nutrition exclusively with breast milk for the first 6 months. Then continue to breastfeed as you add new foods to the diet until they are at least 1 year old.
• Introduce new foods in small portions and one at a time. Monitor for reactions for several days before introducing the next food.
• Wait to give a child cow’s milk until age 1 (this also helps avoid iron deficiency anemia).

For infants that have a family history of food allergies:

• If breastfeeding isn’t possible or is not providing sufficient calories, discuss the choice of formula with your child’s doctor.
• Do not introduce foods that commonly cause allergies, such as nuts, wheat, egg whites and fish, until you have spoken with your child’s doctor.

For older children who have developed allergies, the best way to avoid an allergic reaction is to avoid the food or foods that cause a reaction. Here are some steps you can take:

• Educate yourself so that you can recognize other forms or minor traces of the allergens in the foods your child eats. Read food labels (new labeling laws have made this easier) and ask questions when you eat in restaurants. Educate your child about foods that must be avoided and why.
• Inform all adults who have contact with your child about the allergy and what to do in an emergency.
• Learn cardiopulmonary resuscitation (CPR).
• If your child has a history of severe reactions to certain foods, you and your child should carry epinephrine at all times and use it at the first sign of an allergic reaction. Epinephrine is usually given with an EpiPen; ask your doctor for several of them (so that you can leave one everywhere your child goes often, to be safe), and make sure that everyone who cares for your child knows how to use it.
• Make sure your child’s school or daycare is aware of the allergy.

 HOW LONG WILL FOOD ALLERGIES LAST?

While most children outgrow food allergies, some carry them into adulthood. Teenagers need to be aware of food allergies they had as children and not assume they have outgrown them. In particular, allergies to peanuts, tree nuts, fish and shellfish usually are not outgrown.

There are various treatments for food allergies. The best way to know what will work is to visit your doctor and discuss your food allergy with him/her.

---

---