When the body's immune system reacts abnormally to something a person eats or drinks, it's known as a food allergy.
According to Food Allergy Research and Education (FARE), it’s estimated that 15 million Americans have food allergies. Children are more likely to experience food allergies. Approximately 1 in every 13 children in the United States lives with food allergies.
A food allergy may affect the skin, the gastrointestinal tract, or the respiratory or cardiovascular systems. Many types of foods can be allergens, but certain foods are much more likely than others to trigger an allergic reaction.
According to FARE, eight foods are responsible for 90 percent of food allergies. They are:
- cow's milk
- tree nuts (such as cashews or walnuts)
Symptoms of food allergies may range from mild to severe and they may come on suddenly or develop over several hours.
Because a person's immune system may react to a very small amount of the allergen, food allergies are particularly dangerous and potentially life threatening, especially if breathing is affected. Because of this, people with asthma are at an increased risk for a fatal allergic reaction to food.
Mild symptoms related to a food allergy may include:
- stuffy or runny nose
- itchy, watery eyes
- stomach cramps
Severe symptoms of an allergic reaction to food are:
A milk allergy is a reaction to whey or casein, the proteins found in cow's milk. It’s not the same as lactose intolerance. Milk allergies have been studied more than any other food allergy.
The bad news is that children with milk allergies are much more likely to develop allergic reactions to other foods including eggs, soy, and peanuts.
Most children with milk allergies also develop one or more other atopic diseases such as asthma, allergic rhinitis, or eczema.
Egg allergies occur most often in children and usually resolve at a very young age. However some people may remain allergic to eggs for their entire lives.
A person may be allergic to a certain protein in either the yolk or the egg whites. A person with an allergy to the egg yolk may be able to tolerate egg whites and vice versa. Some people are allergic to both.
Children with peanut allergies rarely grow out of their sensitivity to peanuts, so a peanut allergy is usually a lifelong disorder. Because of this, peanut allergies are particularly serious. Accidental exposure can occur at any time during a person's life. Though rare, a peanut allergy may result in anaphylaxis. This is a severe allergic reaction that can restrict breathing or cause cardiac arrest. Anaphylaxis requires immediate medical attention in the form of a shot of epinephrine (EpiPen). A patient should be watched for several hours after the shot to make sure symptoms don’t return.
Less is known about soy and wheat allergies than the more common allergies discussed above. Likewise, little is known about fish, shellfish, and tree nut allergies except that, like a peanut allergy, they are generally lifelong disorders.
Food allergies are usually diagnosed depending on the severity of symptoms.
If a patient's symptoms are mild, a doctor may recommend keeping a food diary to record all of the foods you eat or drink to pinpoint the culprit. Another way to diagnose a mild food allergy is to remove certain foods from the diet and then slowly reintroduce them to find out if symptoms return.
In the case of more severe allergies, skin or blood tests can identify egg, milk, nut, and shellfish allergies.
As with other types of allergies, avoidance is most often the best medicine. Anyone with a food allergy should be careful when purchasing food at a supermarket or restaurant to make sure there are no traces of the allergen in a food or meal.
Milder symptoms may not require any treatment at all, or a simple over-the-counter antihistamine may resolve the symptoms.
For more serious allergic reactions, a doctor may prescribe steroid medications. Steroids may have serious side effects and shouldn't be used for more than a few days at a time.