When more than one food causes allergy symptoms, you may be living with multiple food allergies (MFA). Allergy testing and food elimination trials can help identify common culprits, but pinpointing every potential food trigger is often challenging.
Food allergies develop when your body mistakes certain foods for harmful substances, triggering an immune response. This reaction causes a release of pro-inflammatory chemicals, like histamines, which are responsible for symptoms like itching, swelling, and digestive upset.
Food allergies are fairly common. One in every 10 adults and 1 in every 13 children have at least one food allergy. When you’re allergic to a variety of foods, you may be living with multiple food allergies.
Multiple food allergies, or MFA for short, is the term used to describe when a person has food allergies to more than three foods.
About 40% of kids with food allergies are allergic to more than one food. These foods can live within the same food group, like different varieties of nuts or fish, or across unrelated food groups, like an allergy to milk and one to peanuts.
MFA isn’t unusual. Being allergic to one food can increase the chance you’ll also have a reaction to a food with similar makeup. This is known as cross-reactivity. In this case, your body can’t tell the difference between food molecules of a similar structure. Your immune system is basically treating similar foods as though they were biologically identical.
Common cross-reactive food groups include:
- animal milks
- fresh and saltwater fish
- crustacean and non-crustacean shellfish
It’s also possible to have MFA across unrelated food groups. For example, approximately 35% of children with peanut allergies will also have a tree nut allergy (peanuts and tree nuts are not actually related).
Overall, MFA is common. A
Food allergy symptoms can be universal, meaning one food allergen can cause the same symptoms as another food allergen. This often makes narrowing down what you’re actually allergic to challenging.
Possible symptoms of any food allergy include:
- hives
- itchy skin
- swelling of lips, face, and eyes
- nausea or vomiting
- diarrhea
- abdominal discomfort
- itchy or watery nose
- throat tightness
- sneezing
- coughing, wheezing, difficulty breathing
- tingling or itching in the mouth or throat
- rapid heart rate
- dizziness or fainting
- confusion
When you live with MFA, you may notice more frequent symptoms compared to someone with a single food allergy. This might happen because your exposure risk increases for each food you’re allergic to. Even when you successfully avoid one allergen, you might still be exposed to another.
You may also notice that your allergy symptoms are frequently severe. Repeat exposure to allergens can make symptoms worse in some people. When you have MFA, you have more opportunities to encounter food allergens back-to-back, compounding symptoms.
All allergies, including food allergies, are caused by immune system dysfunction. For reasons that aren’t fully understood, your immune system mistakes otherwise harmless substances for dangerous pathogens, creating an allergic reaction.
Why this immune dysfunction occurs isn’t clear. Genes, family history, and environment may all play a role.
Diagnosing MFA can be challenging. At your initial doctor visit, your allergist will take a detailed medical history and ask about your symptoms and their circ*mstances.
Sometimes a food culprit is obvious. If you always have hives after drinking milk, for example, your doctor will put milk high on the list of possible allergens. In MFA, however, allergy symptoms likely span a variety of eating scenarios without a clear cause.
To narrow down possible food allergies in MFA, your doctor may recommend allergy testing. A skin prick test or blood test can screen your body’s reactivity to specific foods.
Allergy tests can’t 100% prove you have an allergy to a certain food, however. They can show possible sensitivities but can’t predict if that food will actually cause symptoms or how severe those symptoms might be.
To confirm the results of allergy testing, your allergist may suggest a food elimination trial, also known as an oral food challenge. You’ll gradually eliminate certain foods from your diet and then reintroduce them while your allergist closely monitors you for symptoms.
If done correctly and interpreted by a board certified allergist, skin tests or blood tests are reliable and can rule food allergy in or out.
There’s no cure for food allergies. The only way to prevent them is to actively avoid foods that cause a reaction.
If you’ve accidentally been exposed to a food allergen, your doctor may recommend using an antihistamine for mild symptoms. If your symptoms are severe or you have a history of anaphylaxis, a life threatening allergic reaction, your doctor may recommend using your epinephrine pen and seeking emergency care.
If you have an immunoglobulin E-mediated (IgE-mediated) food allergy, the most common type of food allergy, your doctor may prescribe omalizumab injections. Omalizumab, sold under the brand name Xolair, was approved by the Food and Drug Administration (FDA) in
MFA can be frustrating to manage and may take time to get under control. How much time it takes will depend on how many foods you’re allergic to, how quickly they can be identified, and how completely they can be eliminated from your diet.
Children are likely to outgrow certain food allergies, including allergies to eggs, milk, wheat, and soy. Nut, fish, and shellfish allergies tend to be lifelong.
According to a qualitative study from 2023, many adults with MFA experience persistent stress related to food safety, social limitations, and restrictions on lifestyle freedom. MFA can disrupt cultural use of food and can make trusting others with food preparation difficult.
You may also want to discuss with your allergist whether working with a mental health professional and a dietary specialist can help you develop effective coping strategies that lessen any emotional toll from MFA.
Below are frequently asked questions about multiple food allergies.
How do you live with multiple food allergies?
Successful MFA management involves being proactive about food allergen avoidance by reading ingredient labels, prioritizing food prep sanitation, becoming comfortable asking allergy-related questions in public food spaces, and establishing a food allergy exposure plan with your allergist.
Why do I have so many food sensitivities?
Cross-reactivity, or an immune response to foods with similar makeup, is a common reason why some people experience MFA.
According to the Asthma and Allergy Foundation of America, because of the additional challenges posed by allergen cross-reactivity, it’s important to talk with your allergist-immunologist (allergist) about your symptoms with all foods.
What happens if you keep eating food you’re allergic to?
Continually exposing yourself to a food allergen can potentially make your symptoms worse.
