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A food allergy is an abnormal reaction to a food triggered by your immune system (the part of your body that fights infection). The reaction can be serious or mild. Food intolerance is different than a food allergy. Food intolerance is an unpleasant symptom triggered by food (bloating, gas, stomach cramps). However, it does not involve your immune system.
Symptoms of a food allergy
Symptoms of a food allergy are usually immediate. The most common immediate symptoms of food allergy include:
- hives (large bumps on the skin)
- itchy skin
- itchiness or tingling in the mouth
- metallic taste in the mouth
- coughing, trouble breathing, or wheezing
- throat tightness
The person may also feel that something bad is going to happen, have pale skin (because of low blood pressure), or lose consciousness. The most common chronic illnesses associated with food allergies are eczema (skin disorder) and asthma (respiratory disorder).
A food allergy can be deadly if it is severe enough to cause a reaction called anaphylaxis. This reaction blocks your airway and makes it hard for you to breathe.
What causes food allergies?
Although people can be allergic to any kind of food, most food allergies are caused by tree nuts, peanuts, milk, eggs, soy, wheat, fish, and shellfish. These 8 foods account for 90 percent of food allergies. Most people who have food allergies are allergic to fewer than four foods.
Additionally, studies have found that some food additives, such as yellow food dye and aspartame (artificial sweetener), do cause problems in some people. Sugar and fats are not associated with food allergies.
How is a food allergy diagnosed?
If you have had an abnormal reaction to a food, see your doctor. He or she will examine your symptoms, ask about your health history, put you on an elimination diet (where you take all suspicious foods out of your diet and gradually add them back one at a time), and perform skin and blood tests.
Many children usually outgrow allergies to milk, eggs, soybean products, and wheat. People rarely outgrow allergies to peanuts, tree nuts, fish, and shellfish.
Can food allergies be prevented or avoided?
Once a food allergy is diagnosed, avoid the food that caused it. If you have an allergy, you must read the labels on all the prepared foods you eat. Your doctor can help you learn how to avoid eating the wrong foods. If your child has food allergies, give his or her school and other care providers instructions that list what foods to avoid. Tell them what to do if the food is accidentally eaten. There is no cure for food allergy.
Food allergy treatment
There is no cure for a food allergy. Your doctor will give you antihistamines and oral or topical steroid medicine if you have a mild reaction (itching, sneezing, hives, or rash). A more severe reaction would be treated with a medicine called epinephrine. This medicine must be given quickly to save your life. If you or your child has a severe allergy, your doctor might give you a prescription for an epinephrine pen to carry with you at all times. Your doctor can show you how and when to inject yourself with the pen. A person having an allergic reaction should be taken by ambulance to a hospital emergency room, because the amount of adrenaline being pumped into the body can be dangerous. A doctor can provide medicines to help slow a person’s blood circulation, breathing, and metabolism.
Living with food allergies
Living with food allergies can cause fear and anxiety when you are eating at a restaurant or someone else’s home. You will always wonder if your problem food combined with the rest of the meal. Also, if you have food allergies to most of the 8 common foods, you can feel frustrated by the restrictions in your life.
Questions to ask your doctor
- Is your first bad reaction usually mild or severe?
- Are food allergies inherited?
- Do symptoms appear in a certain order to give you some warning?
- Can you develop food allergies later in life?
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.