If you are allergic to a particular food, you may experience some or all of the following symptoms:
- Itching in your mouth and/or swelling of the lips
- Gastrointestinal (GI) symptoms, such as vomiting, diarrhea, or abdominal cramps and pain
- Hives or some other form of rash and reddening of the skin
- Tightening of the throat and trouble breathing
- Drop in blood pressure
First Allergic Reaction
Usually, the first reaction to a food allergen occurs when you eat that particular food. Sometimes, exposure can occur without your knowledge, such as when a food allergen is a small part of a larger meal or a mixture of different foods. It is the first exposures that prime the immune system to the food.
In the case of peanut allergy, you may not have to eat peanuts or peanut-containing foods to have an allergic reaction. A person who experiences an allergic reaction may have had contact with peanuts in any of the following ways:
- Touching peanuts
- Using a peanut-containing skin care product
- Breathing in peanut dust, such as when in close proximity to people eating peanuts
Cross-reactive Food Allergies
If you have a life-threatening reaction to a certain food, your healthcare professional can show you how to avoid similar foods that may also trigger the reaction. For example, if you have a history of allergy to shrimp, testing may show you are also allergic to other shellfish, such as crab, lobster, and crayfish. This is called cross-reactivity.
If you have had an adverse reaction to a food, see a doctor for evaluation. Although you may think you have had an allergic response, only your doctor can determine if that has been the case.
The guidelines recommend that your doctor first takes your detailed medical history and then performs a physical examination. If a food allergy seems likely, there are tests—such as the skin prick test or a blood test to detect allergen-specific antibodies—that will help identify the possible allergenic foods. However, these approaches alone cannot conclusively diagnose a food allergy.
The only definitive test is an oral food challenge. Because this test can place you at risk for a severe allergic reaction, it must always be performed by a healthcare professional who has the appropriate training and experience with treating the symptoms of a severe allergic reaction.
Prevention and Treatment
There is currently no cure for food allergies, and available treatments only ease the symptoms.
Preventing a food allergy reaction
There are no drugs or treatments available that prevent food allergies. If you have food allergies, the only way to avoid allergic reactions is to avoid allergenic foods. After you and your healthcare professional have identified the food(s) to which you are sensitive, you must remove them from your diet.
Read food labels
Read the list of ingredients on the label of each prepared food that you are considering eating. Many allergens, such as peanuts, eggs, and milk, may appear in prepared foods you normally would not associate them with.
Since 2006, U.S. food manufacturers have been required by law to list the ingredients of prepared foods. In addition, they must use plain language to disclose whether their products contain (or may contain) any of the top eight allergenic foods—eggs, milk, peanuts, tree nuts, soy, wheat, shellfish, and fish.
Treating a Food Allergy Reaction
When you have food allergies, you must be prepared to treat unintentional exposures. Talk to your healthcare professional and plan to protect yourself by taking the following steps:
- Wear a medical alert bracelet or necklace
- Carry an auto-injector device containing epinephrine (adrenaline), such as an EpiPen
- Seek medical help immediately if you are having symptoms
Talk to your healthcare professional to find out what medicines may relieve mild food allergy symptoms that are not part of an anaphylactic reaction. However, be aware that it is very difficult to know which reactions are mild and which may lead to severe reactions (anaphylaxis).
Ways to manage your food allergy after a diagnosis:
- Is there a cure for food allergies? Not yet. The only way to prevent a reaction to a food is to avoid the allergenic food.
- The guidelines recommend that you read food labels carefully.
- If your child has a food allergy, the guidelines suggest seeking nutritional counseling.
- Remember, because some allergies can be outgrown, you should be re-tested periodically to see whether you are still allergic.
Acute Allergic Reactions
An acute, or serious, allergic reaction that comes on rapidly and may result in death is called “anaphylaxis.” It can have many symptoms and affect different parts of the body. Symptoms can include itching, sneezing, difficulty breathing, and blood circulation problems. As a result, it is under-recognized and under-treated. The most common trigger foods for anaphylaxis are peanuts, tree nuts, milk, eggs, fish, and crustaceans (shellfish). To reduce the risk of anaphylaxis, it is essential that you avoid your specific trigger food. If you have a history of anaphylactic reactions to food, you should always carry an epinephrine auto-injector with you.