Food Allergies
A food allergy occurs when the body’s immune system sees a certain food as harmful and reacts by causing allergic symptoms. However, not all people who react to a certain food have an allergy. They may have a food intolerance, and food intolerance does not involve the immune system. Examples of food intolerance are lactose intolerance, gluten intolerance or sulfite sensitivity.
For individuals who do have food allergies, eight types of food account for almost 90% of all food allergies. Those foods include: Cow’s milk, eggs, tree nuts, peanuts, shellfish, wheat, soy, and fish.
What are the Symptoms of Food Allergies?
Symptoms of a food allergy can range from mild to severe. Just because an initial reaction causes few problems doesn’t mean that all reactions will be similar. A food that triggered only mild symptoms on one occasion may cause more severe symptoms at another time. Symptoms of an allergic reaction may involve the skin, the gastrointestinal tract, the cardiovascular system and the respiratory tract. The most common food allergy symptoms include:
- Tingling or itching in the mouth
- Hives, itching or eczema
- Swelling of the lips, face, tongue and throat or other parts of the body
- Wheezing, nasal congestion or trouble breathing
- Abdominal pain, diarrhea, nausea or vomiting
- Dizziness, lightheadedness or fainting
- Repetitive cough
- Shock or circulatory collapse
- Tight, hoarse throat; trouble swallowing
- Weak pulse
- Pale or blue coloring of skin
- Anaphylaxis
Most food-related symptoms occur within two hours of ingestion; often they start within minutes. In some very rare cases, the reaction may be delayed by four to six hours or even longer. Delayed reactions are most typically seen in children who develop eczema as a symptom of food allergy and in people with a rare allergy to red meat caused by the bite of a lone star tick.
How is a Food Allergy Diagnosed?
A food allergy will usually cause some sort of reaction every time the trigger food is eaten. Symptoms can vary from person to person, and you may not always experience the same symptoms during every reaction. Allergic reactions to food can affect the skin, respiratory tract, gastrointestinal tract and cardiovascular system. It is impossible to predict how severe the next reaction might be, and all patients with food allergies should be carefully counseled about the risk of anaphylaxis, a potentially fatal reaction that is treated with epinephrine (adrenaline).
While food allergies may develop at any age, most appear in early childhood. If you suspect a food allergy, contact the Sinus Institute of Atlanta to schedule a consultation. During your consultation at the Sinus Institute of Atlanta, Dr. Pradeep Sinha will ask detailed questions about your medical history and your symptoms. Be prepared to answer questions about:
- What and how much you ate
- How long it took for symptoms to develop
- What symptoms you experienced and how long they lasted.
After taking your history, Dr. Sinha may order skin tests and/or blood tests, which indicate whether food-specific immunoglobulin E (IgE) antibodies are present in your body:
- Skin prick tests provide results in about 20 minutes. A liquid containing a tiny amount of the food allergen is placed on the skin of your arm or back. Your skin is pricked with a small, sterile probe, allowing the liquid to seep under the skin. The test, which isn’t painful but can be uncomfortable, is considered positive if a wheal (resembling the bump from a mosquito bite) develops at the site where the suspected allergen was placed. As a control, you’ll also get a skin prick with a liquid that doesn’t contain the allergen; this should not provoke a reaction, allowing comparison between the two test sites.
- Blood tests, which are a bit less exact than skin tests, measure the amount of IgE antibody to the specific food(s) being tested. Results are typically available in about a week and are reported as a numerical value.
Dr. Sinha will use the results of these tests in making a diagnosis. A positive result does not necessarily indicate that there is an allergy, though a negative result is useful in ruling one out.
In some cases, Dr. Sinha may recommend an oral food challenge, which is considered the most accurate way to make a food allergy diagnosis. During an oral food challenge, which is conducted under strict medical supervision, the patient is fed tiny amounts of the suspected trigger food in increasing doses over time, followed by a few hours of observation to see if a reaction occurs. This test is helpful when the patient history is unclear or if the skin or blood tests are inconclusive. It also can be used to determine if an allergy has been outgrown. Because of the possibility of a severe reaction, an oral food challenge should be conducted only by experienced allergists in a doctor’s office or at a food challenge center, with emergency medication and equipment on hand.
Managing a Food Allergy
The primary way to manage a food allergy is to avoid consuming the food that causes you problems. Carefully check ingredient labels of food products and learn whether what you need to avoid is known by other names.
The Food Allergy Labeling and Consumer Protection Act of 2004 (FALCPA) mandates that manufacturers of packaged foods produced in the United States identify, in simple, clear language, the presence of any of the eight most common food allergens – milk, egg, wheat, soy, peanut, tree nut, fish and crustacean shellfish – in their products. The presence of the allergen must be stated even if it is only an incidental ingredient, as in an additive or flavoring. Some goods also may be labeled with precautionary statements, such as “may contain,” “might contain,” “made on shared equipment,” “made in a shared facility” or some other indication of potential allergen contamination. There are no laws or regulations requiring those advisory warnings and no standards that define what they mean. If you have questions about what foods are safe for you to eat, talk with your allergist.
Be advised that the FALCPA labeling requirements do not apply to items regulated by the U.S. Department of Agriculture (meat, poultry and certain egg products) and those regulated by the Alcohol and Tobacco Tax and Trade Bureau (distilled spirits, wine and beer). The law also does not apply to cosmetics, shampoos and other health and beauty aids, some of which may contain tree nut extracts or wheat proteins.
Avoiding a food allergen is easier said than done. While labeling has helped make this process a bit easier, some foods are so common that avoiding them is daunting. A dietitian or a nutritionist may be able to help. These food experts will offer tips for avoiding the foods that trigger your allergies and will ensure that even if you exclude certain foods from your diet, you still will be getting all the nutrients you need. Special cookbooks and support groups, either in person or online, for patients with specific allergies can also provide useful information.
Eating out
Be extra careful when eating in restaurants. Waiters (and sometimes the kitchen staff) may not always know the ingredients of every dish on the menu. Depending on your sensitivity, even just walking into a kitchen or a restaurant can cause an allergic reaction.
Consider using a “chef card” – available through many websites – that identifies your allergy and what you cannot eat. Always tell your servers about your allergies and ask to speak to the chef, if possible. Stress the need for preparation surfaces, pans, pots and utensils that haven’t been contaminated by your allergen and clarify with the restaurant staff what dishes on the menu are safe for you.
Many people with food allergies wonder whether their condition is permanent. There is no definitive answer. Allergies to milk, eggs, wheat and soy may disappear over time, while allergies to peanuts, tree nuts, fish and shellfish tend to be lifelong.