A food allergy occurs when the body’s immune system sees a certain food as harmful and reacts by causing symptoms.
This is an allergic reaction. Foods that cause allergic reactions are called allergens. 


Normally, your immune system protects you from germs and disease. It does this by making antibodies that help you fight
off bacteria, viruses, and other tiny organisms that can make you sick. But if you have a food allergy, your immune system mistakenly treats something in a certain food as if it’s really dangerous for you.


Allergic reactions can involve the skin, mouth, eyes, lungs, heart, gut, and brain. Mild and severe symptoms can lead to a serious allergic reaction called anaphylaxis. This reaction usually involves more than one part of the body and can worsen quickly. Anaphylaxis must be treated right away to provide the best chance for improvement and prevent serious, potentially life-threatening complications. 


The same sort of thing happens with any allergy, whether it’s a medicine like penicillin, pollen in the air, such as grasses, weeds, and trees, or a food, like peanuts. So the thing itself isn’t harmful, but the way your body reacts to it is.

What are food allergies?




Symptoms typically appear within minutes to several hours after eating the food to which you are allergic. An allergic reaction to food can affect the skin, the gastrointestinal tract, the respiratory tract and, in the most serious cases, the cardiovascular system.


An allergic reaction typically triggers symptoms in the nose, lungs, throat, sinuses, ears, lining of the stomach, or on the skin. For some people, allergies can also trigger symptoms of asthma. In the most serious cases, a life-threatening reaction called anaphylaxis can occur.


A number of different allergens are responsible for allergic reactions. The most common include:


  • Pollen

  • Dust

  • Food

  • Insect stings

  • Animal dander

  • Mold

  • Medications

  • Latex


Reactions can range from mild to severe, including the potentially life-threatening condition anaphylaxis.

Remember that reactions can be unpredictable. The first signs of a reaction can be mild, but symptoms can worsen quickly. And what caused a mild reaction one time can lead to a severe reaction the next.

Keep in mind that children may communicate their symptoms differently than adults. Learn more about how a child might describe a reaction.


Skin Rash





Mild to moderate symptoms may include one or more of
the following:


  • Hives (reddish, swollen, itchy areas on the skin)

  • Eczema flare (a persistent dry, itchy rash)

  • Redness of the skin, particularly around the mouth or eyes

  • Itchy mouth or ear canal

  • Nausea or vomiting

  • Diarrhea

  • Stomach pain

  • Nasal congestion or a runny nose

  • Sneezing

  • Slight, dry cough

  • Odd taste in the mouth

Severe symptoms may include one or more of the following:

Swelling of the lips, tongue, and/or throat that blocks breathing

  • Trouble swallowing

  • Shortness of breath or wheezing

  • Turning blue

  • Drop in blood pressure (feeling faint, confused, weak, passing out)

  • Loss of consciousness

  • Chest pain

  • A weak or “thready” pulse

  • Sense of “impending doom”​

Severe symptoms, alone or combined with milder symptoms, may be signs of life-threatening anaphylaxis. This requires immediate treatment.

Epinephrine is the first-line treatment for anaphylaxis, and your anaphylaxis plan should be individualized by your healthcare provider. Delays in administering epinephrine for severe or persistent symptoms can be very dangerous, especially when the delay is an hour or longer.