More than 12 million (or 4%) of Americans have food allergies of which it is estimated that about 3 million are children*.
What is a food allergy?
A food allergy is an exaggerated immune response triggered by an ordinarily harmless food such as peanuts,eggs or cow’s milk. The cause of food allergies is related to your body making a type of allergy-producing substance called immunoglobulin E (IgE) antibodies to a particular food.
Many people confuse a true food allergy with a food intolerance which is more common. A food intolerance refers to an abnormal response to a food or food additive that does not involve the immune system. In a true food allergy, the immune system produces antibodies and histamine in response to the specific food.
What foods cause food allergies?
Any food can cause an allergic reaction. However, eight foods account for 90% of all food-allergic reactions in the U.S.:
- tree nuts (i.e. almonds, walnuts, cashews, pistachios, pecans)
The most common allergens are proteins. These allergens cause reactions even after being cooked or digested. Other allergens such as fruits and vegetables usually cause reactions if eaten raw and the reactions are limited to the mouth and throat.
What are the symptoms of food allergies?
Symptoms usually begin immediately, within 2 hours after eating. Rarely, the symptoms may begin hours after eating the offending food.
If you develop symptoms shortly after eating a specific food, you may have a food allergy.
Key symptoms include:
- Hoarse voice
Other symptoms that may occur include:
- Abdominal pain
- Difficulty swallowing
- Itching of the mouth, throat, eyes, skin, or any area
- Lightheadedness or fainting
- Nasal congestion
- Runny nose
- Eczema (atopic dermatitis)
- Angioedema, especially of the eyelids, face, lips, and tongue
- Shortness of breath
- Stomach cramps
Symptoms of mouth (oral) allergy syndrome:
- Itchy lips, tongue, and throat
- Swollen lips (sometimes)
Food allergies can trigger or worsen asthma, eczema, or other disorders.
In severe reactions, you may go into anaphylaxis, at which time,you should call 911 or have someone take you to the emergency room right away.
How is food allergy diagnosed?
Allergy testing including blood (RAST) and/or skin tests are sometimes used to confirm that you have an allergy. Challenge testing may also be done. Elimination diets can be useful in determining the allergy. This involves avoidance of the suspected foods until your symptoms disappear. Then the foods are reintroduced one at a time to see if you develop an allergic reaction.
Who gets food allergies?
The incidence of food allergy is highest in young children . A food allergy frequently starts in childhood, but it can begin at any age.
Fortunately, many children will outgrow their allergy to milk, egg, wheat, and soy by the time they are 5 years old if they avoid the offending foods when they are young. Allergies to peanuts, tree nuts, and shellfish tend to be lifelong.
Food additives — such as dyes, thickeners, and preservatives – may rarely cause an allergic or intolerance reaction.
An allergy syndrome that affects the mouth and tongue may occur after eating certain fresh fruits and vegetables. These foods contain substances similar to certain pollens. For example, melon contains substances similar to ragweed pollen, and apples have allergens similar to tree pollen.
Many Americans believe they have food allergies, while in reality fewer than 1% have true allergies. Most symptoms are caused by intolerances to foods such as:
- Corn products
- Cow’s milk and dairy products (lactose intolerance)
- Wheat and other gluten-containing grains (celiac disease)
How are food allergies treated?
Treatment is determined on an individual basis as prescribed by your physician. Please contact our office to schedule an appointment with one of our allergy and asthma specialists.
Is there a cure for food allergies?
There is no cure for food allergies; however, many children will outgrow some or all of their allergies.
What are the possible complications of food allergies?
The most serious complication is anaphylaxis, a severe, whole-body allergic reaction that is life threatening. Anaphylaxis occurs in 20% of allergic reactions to peanuts and tree nuts**. Food allergies can also trigger or worsen asthma, eczema, or other disorders.
How do you prevent food allergies?
Breastfeeding may help prevent allergies. Otherwise, there is no known way to prevent food allergies except to delay introducing allergy-causing foods to infants until their gastrointestinal tract has had a chance to mature. The timing for this varies from food to food and from baby to baby.
How do you avoid food allergic reactions?
Avoiding the offending foods may be easy if the food is uncommon or easily identified. However, you may need to severely restrict your diet, carefully read all package ingredients, and ask detailed questions when eating away from home.
*Branum AM, Lukacs SL. Food allergy among U.S. children: Trends in prevalence and hospitalizations. NCHS data brief, no 10. Hyattsville, MD: National Center for Health Statistics. 2008.
**Sicherer SH, et al. Clinical features of acute allergic reactions to peanut and tree nuts in children. Pediatrics 1998;102(1) e6.