Food Allergy

Researchers at the Johns Hopkins Children’s Center are finding novel treatments for food allergies, but a new approach has brought them closer to a true cure than ever before. While a real cure for food allergies is at least 10 years away, new therapies in the past few years have proven curative in a handful of patients, illuminating much about the disease and paving the way to a cure for others, says Robert Wood, M.D., division chief of pediatric Allergy and Immunology.

One approach in particular, called oral immunotherapy (OIT), has shown decidedly promising results in patients with milk and egg allergies and has the potential to be used in other types of allergies. OIT involves giving children increasingly higher doses of the very food they are allergic toward to gradually retrain their immune systems to tolerate it without a reaction.

“With oral immunotherapy, we have enlisted an unlikely ally — the very enemy, indeed — that causes allergic reactions in the first, place. The allergens that cause allergic reactions may turn out to be our best hope for a cure,” Wood says. 

What is a food allergy?

A food allergy occurs when the immune system mistakenly identifies a food substance, such as a peanut or milk (the allergen), as a hostile organism and produces antibodies to attack the allergen. About 2 million Americans have food allergies. Food allergies have increased in the last decade. They may be also becoming harder to outgrow and more persistent, according to the latest research from Hopkins Children’s Center. A food allergy can develop shortly after birth or any time during childhood. Even adults can develop food allergies to foods that they have eaten in the past.

Even though the two are often confused, food allergy and food intolerance are two distinctly different conditions. Food intolerance is NOT a food allergy. A food allergy always involves an immune system reaction to a certain food, while a food intolerance does not have an immune component. Food intolerance typically produces gastrointestinal disturbance marked by bloating, nausea and indigestion, some of which can also occur with certain food allergies. A true allergy, on the other hand, causes an immune reaction, involving the production of antibodies toward the allergenic food, with symptoms like hives, itching of the mouth and throat, swelling of the face, lips, tongue and throat and difficulty breathing. 

Symptoms

• Hives (urticaria), red swollen spots on the skin

• Eczema (atopic dermatitis), scaly itchy dry patches of skin

• Asthma, marked by wheezing, coughing, difficulty breathing

• Abdominal pain, vomiting, diarrhea

Food allergies can cause a severe life-threatening reaction known as anaphylaxis, which is always an emergency.

The symptoms of anaphylaxis are:

• Difficulty breathing

• Confusion

• Rapid heart beat

• Swelling of the lips, tongue, throat

• Wheezing

• Confusion

• Bluish skin (cyanosis)

• Light-headedness, dizziness, fainting

• Hives and generalized itching

• Anxiety

• Heart palpitations

• Nausea, vomiting

• Diarrhea

• Abdominal pain or cramping

• Cough

Diagnosis

Children with suspected food allergies should be referred to a pediatric allergist. Diagnosis is made based on the following:

• A physical exam

• History of symptoms, including frequency, severity and diet/nutrition

• Allergy skin test, injecting a small amount of the suspected allergen under the skin

• In some cases, blood tests that measure the presence of antibodies in the blood to certain foods may be helpful. However, these tests are not always reliable as a child can have a negative test result (no antibodies detected) and still be allergic. The opposite is also true: A test may detect antibodies to certain foods, but the child may never have an allergic reaction.

• Food challenges, a highly controlled experiment under the observation of a doctor and/or a nurse, can render a definitive diagnosis. During the food challenge, a small amount of the suspected allergen is given to the child in the doctor’s office and the child’s reaction is observed.

Treatment

The best way to prevent an allergic reaction is to avoid food(s) that have caused reactions in the past. Children who have had severe reactions in the past, should carry an EpiPen® (injectable epinephrine) for treatment of anaphylaxis. An identification bracelets/necklace stating the allergy should be worn.

At Hopkins Children’s Center, researchers are conducting studies to find new treatments and therapies for food allergies. For example, a study of children with milk allergy is underway to determine whether the immune system can be retrained to ignore the offending food by giving children increasingly higher doses of milk protein, a method known as progressive desensitization. 

When to Call for Help

If your child develops some of the above symptoms, call your pediatrician. If you think your child is having a severe reaction (anaphylaxis), call 911 or go to the nearest emergency room.