What are food allergies?
Food allergies occur when your body overreacts to the proteins in specific foods. This overreaction is called an allergic reaction.
What are the types of food allergies?
You can have an allergy to any type of food. Eight types of food account for about 90% of all food allergies. These foods are:
How common are food allergies?
Food allergies affect more than 50 million Americans. About 4% of adults have food allergies. Food allergies affect up to 6% of children.
How do food allergies affect my body?
Your immune system identifies and destroys harmful bacteria and viruses. When you have a food allergy, your immune system mistakenly identifies a food protein as something harmful. Coming in contact with that protein triggers an allergic reaction.
Are food allergies the same as food intolerances?
Food allergies are not the same as food intolerances. Allergies cause a response in your immune system. Allergies can be life-threatening.
Food intolerances cause a response in your digestive system. You may be able to eat a small amount of a food you are intolerant to without experiencing symptoms. Intolerances can be uncomfortable but aren’t usually dangerous.
Symptoms and Causes
What causes food allergies?
Food allergies tend to run in families. If you have other allergic conditions, such as hay fever or eczema, you may be more likely to have a food allergy. You are also more likely to experience food allergies if you have asthma.
What are the symptoms of food allergies?
Usually, you experience food allergy symptoms within two hours of eating. The symptoms of food allergies can range from mild to severe. If you have an allergic reaction, you may experience:
- Hives or skin rash.
- Swelling of the lips or eyelids.
- Itching mouth and throat, tongue swelling.
- Hoarse voice, difficulty swallowing.
- Cough, wheezing or shortness of breath.
- Abdominal pain, vomiting , diarrhea.
- Lightheadedness or loss of consciousness.
Are there any life-threatening symptoms of food allergies?
The most severe allergic reaction to a food is anaphylaxis. Anaphylaxis is a rapidly progressive reaction that sends your body into shock. It can make it hard or impossible to breathe. Without medical treatment, anaphylaxis can be life-threatening.
Diagnosis and Tests
How are food allergies diagnosed?
Food allergies cause similar reactions each time you eat a trigger food. To make a diagnosis, a healthcare provider may ask you:
- How long it takes for your symptoms to develop.
- What and how much of a certain trigger food you ate.
- What symptoms you experience and for how long.
What tests are used to diagnose food allergies?
If you suspect you have a food allergy, allergy/immunology providers can perform a skin test to confirm it. During a skin test, your healthcare provider:
- Applies a small amount of different types of allergens (allergy-causing substances) to your skin on your arms or back.
- Makes tiny pricks or scratches through the allergens.
- Measures your reactions to the allergens after tests have been in place for 15 minutes.
Areas of your skin that become red and itchy indicate an allergy. Your healthcare provider uses this information to determine what you’re allergic to.
Your healthcare provider may also use a radioallergosorbent blood test (RAST). A RAST checks the levels of allergic antibody to different allergens in your blood. Raised levels of specific antibodies can indicate an allergy.
Management and Treatment
How are food allergies treated?
When you know what foods you are allergic to, the best approach is to strictly eliminate those foods from your diet and to have emergency medications including epinephrine autoinjectors available at all times in case of accidental ingestion and reaction. It’s important to seek emergency medical care immediately after using an epinephrine autoinjector. Wearing a medical alert identification indicating your food allergies is also recommended.
Your healthcare provider may prescribe medicines that reduce your allergic reaction symptoms. These medicines include:
- Epinephrine (for example, EpiPen® or Auvi-Q), a lifesaving emergency medication that immediately begins reversing symptoms of anaphylaxis.
- Antihistamines, medications that reduce itching or congestion.
- Corticosteroids to reduce swelling if you have a severe allergic reaction.
How can I avoid food allergy triggers?
To avoid the foods you are allergic to, you must carefully check the ingredient labels on food products. Food manufacturers must clearly state on the label if a product contains any of the eight most common food allergens.
Some labels use precautions such as “may contain” or “made on shared equipment.” If you have any questions about what you can and can’t eat, ask your healthcare provider.
How can I prevent food allergies?
There is no known way to prevent food allergies in adults. In babies, breastfeeding in the first six months of life may prevent milk allergy. Early introduction of highly allergenic foods such as peanut protein and eggs into the diet may also have a preventative effect. Please discuss with your healthcare provider.
Outlook / Prognosis
What is the outlook for people with food allergies?
You can live a healthy life with a food allergy. If you have a food allergy, you need to carefully avoid all foods and ingredients that cause allergic reactions.
You may also need to take a nutritional supplement to replace any nutrients lost by avoiding your trigger foods. Speak with your healthcare provider or dietitian before starting a new eating plan.
When should I see my healthcare provider for a food allergy?
If eating specific foods causes uncomfortable symptoms, see a healthcare provider for diagnosis and treatment.
When should I go to the ER?
Without medical treatment, allergic reactions can be life-threatening. Go to the ER or call 911 if you experience:
- Difficulty breathing.
- Chest tightness.
- Hives all over your body.
- Tingling hands, feet or lips.
- Throat swelling that constricts your airway.
A note from Cleveland Clinic
Food allergies occur when your body mistakenly triggers an immune response to certain foods. This immune response, or allergic reaction, can cause a variety of symptoms such as hives, swelling or difficulty breathing. In severe cases, you may experience a life-threatening reaction called anaphylaxis. Once you know what foods you are allergic to, the best way to manage your allergy is to avoid those specific foods. Healthcare providers can prescribe medications that reverse anaphylaxis and other allergy symptoms.
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