There's no perfect test used to confirm or rule out a food allergy. Your doctor will consider a number of factors before making a diagnosis. These factors include.
- Your symptoms. Give your doctor a detailed history of your symptoms — which foods, and how much, seem to cause problems.
- Your family history of allergies. Also share information about members of your family who have allergies of any kind.
- A physical examination. A careful exam can often identify or exclude other medical problems.
A skin test. A skin prick test can determine your reaction to a particular food. In this test, a small amount of the suspected food is placed on the skin of your forearm or back. A doctor or another health professional then pricks your skin with a needle to allow a tiny amount of the substance beneath your skin surface.
If you're allergic to a particular substance being tested, you develop a raised bump or reaction. Keep in mind, a positive reaction to this test alone isn't enough to confirm a food allergy.
A blood test. A blood test can measure your immune system's response to particular foods by measuring the allergy-related antibody known as immunoglobulin E (IgE).
For this test, a blood sample taken in your doctor's office is sent to a medical laboratory, where different foods can be tested.
Elimination diet.You may be asked to eliminate suspect foods for a week or two and then add the food items back into your diet one at a time. This process can help link symptoms to specific foods. However, elimination diets aren't foolproof.
An elimination diet can't tell you whether your reaction to a food is a true allergy instead of a food sensitivity. Also, if you've had a severe reaction to a food in the past, an elimination diet may not be safe.
- Oral food challenge. During this test, done in the doctor's office, you'll be given small but increasing amounts of the food suspected of causing your symptoms. If you don't have a reaction during this test, you may be able to include this food in your diet again.
The only way to avoid an allergic reaction is to avoid the foods that cause signs and symptoms. However, despite your best efforts, you may come into contact with a food that causes a reaction.
For a minor allergic reaction, over-the-counter or prescribed antihistamines may help reduce symptoms. These drugs can be taken after exposure to an allergy-causing food to help relieve itching or hives. However, antihistamines can't treat a severe allergic reaction.
For a severe allergic reaction, you may need an emergency injection of epinephrine and a trip to the emergency room. Many people with allergies carry an epinephrine autoinjector (Adrenaclick, EpiPen). This device is a combined syringe and concealed needle that injects a single dose of medication when pressed against your thigh.
If your doctor has prescribed an epinephrine autoinjector:
- Be sure you know how to use the autoinjector. Also, make sure the people closest to you know how to administer the drug — if they're with you in an anaphylactic emergency, they could save your life.
- Carry it with you at all times. It may be a good idea to keep an extra autoinjector in your car or in your desk at work.
- Always be sure to replace epinephrine before its expiration date or it may not work properly.
While there's ongoing research to find better treatments to reduce food allergy symptoms and prevent allergy attacks, there isn't any proven treatment that can prevent or completely relieve symptoms.
Treatments being studied are:
Anti-IgE therapy. The medication omalizumab (Xolair) interferes with the body's ability to use IgE. The drug is currently being studied for treatment of allergic asthma and food allergies.
This treatment is still considered experimental, and more research needs to be done on the drug's long-term safety. It has been associated with a potential increased risk of anaphylaxis.
Oral immunotherapy. Researchers have been studying the use of oral immunotherapy as a treatment for food allergy. Small doses of the food you're allergic to are swallowed or placed under your tongue (sublingual). The dose of the allergy-provoking food is gradually increased.
Initial results look promising, even in people with peanut, egg and milk allergies. But more research needs to be done to ensure that this treatment is safe.
Early exposure. In the past, it's been generally recommended that children avoid allergenic foods to reduce the likelihood of developing allergies. But in a recent study, high-risk infants — such as those with atopic dermatitis or egg allergy or both — were selected to either ingest or avoid peanut products from 4 to 11 months of age until 5 years of age.
Researchers found that high-risk children who regularly consumed peanut protein, such as peanut butter or peanut-flavored snacks, were 70 to 86 percent less likely to develop a peanut allergy. These findings may impact food allergy guidelines in the future.
Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this disease.
Lifestyle and home remedies
One of the keys to preventing an allergic reaction is to completely avoid the food that causes your symptoms.
Don't assume. Always read food labels to make sure they don't contain an ingredient you're allergic to. Even if you think you know what's in a food, check the label. Ingredients sometimes change.
Food labels are required to clearly list whether they contain any common food allergens. Read food labels carefully to avoid the most common sources of food allergens: milk, eggs, peanuts, tree nuts, fish, shellfish, soy and wheat.
When in doubt, say no thanks. At restaurants and social gatherings, you're always taking a risk that you might eat a food you're allergic to. Many people don't understand the seriousness of an allergic food reaction and may not realize that a tiny amount of a food can cause a severe reaction in some people.
If you have any suspicion at all that a food may contain something you're allergic to, steer clear.
Involve caregivers. If your child has a food allergy, enlist the help of relatives, baby sitters, teachers and other caregivers. Make sure that they understand how important it is for your child to avoid the allergy-causing food and they know what to do in an emergency.
It's also important to let caregivers know what steps they can take to prevent a reaction in the first place, such as careful hand-washing and cleaning any surfaces that might have come in contact with the allergy-causing food.
Research on alternative food allergy treatments is limited. However, many people do try them and claim that certain treatments help.
Acupuncture point injection therapy has been found to be beneficial for the treatment of hives, although more research is needed to confirm these findings. If you decide to try one of these treatments, be sure you work with an experienced and certified provider.
Coping and support
A food allergy can be a source of ongoing concern that affects life at home, school and work. Daily activities that are easy for most families, such as grocery shopping and meal preparation, can become occasions of stress for families and caregivers living with food allergies.
Keep these strategies in mind to help manage your or your child's food allergy-related stress:
Connect with others. The opportunity to discuss food allergies and exchange information with others who share your concerns can be very helpful.
Many internet sites and nonprofit organizations offer information and forums for discussing food allergies. Some are specifically for parents of children with food allergies. The Food Allergy Research & Education website can direct you to support groups and events in your area.
- Educate those around you. Make sure family and caregivers, including baby sitters and school staff, have a thorough understanding of your child's food allergy.
- Address bullying. Children are often bullied because of food allergies at school. Discussing your child's allergy with school personnel greatly reduces your child's risk of being a bullying target.
Preparing for your appointment
Because doctor's appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well-prepared for your appointment. Here's some information to help you get ready for your appointment and what to expect from your doctor.
- Write down any symptoms you've had, including any that may seem unrelated to the reason for which you scheduled the appointment.
- Write down key personal information, including any major stresses or recent life changes.
- Make a list of all medications, vitamins and supplements that you're taking.
- Take a family member or friend along, if possible. Sometimes it can be difficult to remember all the information provided to you during an appointment. Someone who accompanies you may recall something that you missed or forgot.
- Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important in case time runs out. Some basic questions to ask your doctor include:
- Is my condition likely caused by a food allergy or another reaction?
- What kinds of tests do I need?
- Is my condition likely temporary or long lasting?
- What types of treatment are available, and which do you recommend?
- What are the alternatives to the primary approach that you're suggesting?
- I have these other health conditions. How can I best manage these conditions together?
- Are there any dietary restrictions that I need to follow?
- Should I see a specialist? What will that cost, and will my insurance cover seeing a specialist?
- Is there a generic alternative to the medicine you're prescribing me?
- Do you have any printed material that I can take home with me? What websites do you recommend visiting?
If your child is seeing the doctor for a food allergy, you may also want to ask:
- Is my child likely to outgrow his or her allergy?
- Are there alternatives to the food or foods that trigger my child's allergy symptoms?
- How can I help keep my child with a food allergy safe at school?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may save time to go over any points you want to spend more time on. Your doctor may ask:
- When did you begin experiencing symptoms?
- How severe were your symptoms?
- How long did it take symptoms to appear after eating the food you suspect you're allergic to?
- Did you take any over-the-counter allergy medications such as antihistamines, and if so, did they help?
- Does your reaction always seem to be triggered by a certain food?
- How much food did you eat before the reaction?
- Was the food that caused the reaction cooked or raw?
- Do you know how the food was prepared?
- What, if anything, seems to improve your symptoms?
- What, if anything, appears to worsen your symptoms?
What you can do in the meantime
If you suspect you have a food allergy, avoid exposure to the food altogether until your doctor's appointment. If you do eat the food and have a mild reaction, over-the-counter antihistamines may help relieve symptoms. If you have a more severe reaction and any signs and symptoms of anaphylaxis, seek emergency help.