Understanding the Signs of Your Food Allergy

Oh my god, what is that?
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Everyone has been raving about your Aunt Bev’s apple pie, but as soon as you eat it, you don't feel so well. Your stomach begins to feel upset and your throat feels kind of funny. Are you coming down with something or perhaps you are experiencing an allergic reaction? Now that you think about it, the symptoms seem somewhat familiar, as this isn't the first time you felt this way. Rather than assuming it is nothing, it is important to share these experiences with your doctor to rule out food allergies. By working with your doctor you will not only get to the bottom of these symptoms but also know once and for all how to manage and avoid any possible life threatening situations. 

While symptoms of food allergies can vary from person to person, they classically begin within two hours of eating a trigger food. A food allergy is an immune system overreaction to a particular protein found in a food. The body reacts as if the food allergen is a toxin or foreign invader, and the body tries to fight it off. An estimated 15 million American have been diagnosed with food allergies, some with acute reactions, and others with life-threatening reactions. While food allergy symptoms tend to occur within a short time after ingesting, food sensitivities, such as lactose intolerance or an auto-immune disorder such as celiac disease, may be delayed up to 12 hours. 

Acute symptoms are those that occur shortly after ingestion of the offending food. These symptoms tend to affect the skin, stomach, airways, eyes, or entire body. Some of the signs of food allergy are:

Skin Reactions

Food allergies can cause skin rashes, such as:

  • Hives: Raised red welts that move around the body and look like mosquito bites and are itchy
  • Eczema: A scaly, itchy rash that may blister or peel
  • Swelling: Swollen tissue around the face and lips, especially

Discuss with your doctor possible treatments for these skin irritants.  Doctors often suggest treating skin reactions with an oral antihistamine, such as Benadryl (diphenhydramine) or topical agents like steroid creams, calamine lotion, or oatmeal baths. It is important to take a close look at the hives, and note whether they last for a short time or seem to be lasting longer than a few hours. This can help your doctor to determine the cause of the hives.  Also if any hives are found in the mouth or throat, be sure to seek immediate medical attention as they can lead to life-threatening situations. 

Stomach/Digestive Tract Symptoms

Food allergies may cause stomach or intestinal symptoms, which is a way the body gets rid of the offending food, such as:

  • Nausea: Upset stomach, feeling that you may throw up
  • Abdominal pain: Pain in your stomach or abdominal area
  • Vomiting: Throwing up
  • Diarrhea: Loose, watery stool, more than three times a day

While a chronic stomachache may be a sign that you have a food allergy,  it may be a sign of some other digestive issue.  Lactose intolerance, celiac disease, inflammatory bowel disease (IBD), and ulcers are among other conditions that may present similar symptoms.  While antihistamines can help allergies, they do not help resolve the symptoms of these other conditions. 

If your symptoms are primarily digestive, you should seek out a gastroenterologist to help you pinpoint the problem and find solutions.


Food allergies that affect the airways are extremely serious and need to be handled immediately.  It is important to understand your allergy and what reaction can occur if exposed to the food allergen.  The allergy can affect the lungs, mouth, throat, and ability to breathe. If you have asthma and food allergies, you are at a higher risk for having a severe allergic reaction that involves trouble breathing.  Those who have been diagnosed with an anaphylactic allergy must always carry medication in the event of an emergency.  

Some symptoms of allergies that affect the airways include:

  • Wheezing: A high-pitched sound that is made when trying to breathe through swollen breathing tubes
  • Coughing: This may be due to an itchy throat or swelling which makes breathing more difficult
  • Allergic rhinitis: Runny nose
  • Angioedema: Swelling of lips, tongue, eyes, or face

Discuss with your doctor how to treat mild swelling, a rash on your lips or tongue.  For some people, oral antihistamines, such as Benadryl, are the course of treatment.  However, those who are at risk of swelling of the airways, trouble breathing, having a short, barking cough, or have trouble swallowing may be showing signs of anaphylaxis. These situations may require that the person carry and use, if needed, an auto-injectable epinephrine dose, and seek emergency medical treatment.


Allergic reactions of the eyes are called allergic conjunctivitis. Symptoms are:

  • Redness
  • Itching
  • Watering
  • Swelling

Discuss with your doctor about how to treating itchy, watery eyes.  For many people, the use of an oral antihistamine will help resolve symptoms. 

Severe, Full-Body Reactions (Anaphylaxis)

Anaphylaxis is a type of shock (loss of blood pressure) caused by an allergic reaction. This type of reaction can happen within minutes of exposure to the allergen, although for some it may not occur for up to two hours.  Due to the severity of this reaction, it is important not to ignore the first sign of a reaction.  It may involve some or all of the symptoms outlined above, plus any of the additional reactions:

  • A sense of impending doom - Patients often report this feeling as they are overcome by the bodies immune system reaction to exposure to the allergen
  • Loss of consciousness - This is also accompanied by low blood pressure and decreased heart rate
  • Difficulty breathing
  • Pale skin
  • Dizziness, lightheadedness - This is often due to a drop in blood pressure

Anaphylaxis is a life-threatening emergency. If you experience any of the symptoms of anaphylaxis, call 911 immediately and administer first aid for anaphylaxis.

Anaphylaxis can progress rapidly and can cause death within 30 minutes of the onset of symptoms if not promptly treated with emergency epinephrine. If you think you may be experiencing anaphylaxis, do not wait to see if your symptoms improve. In some cases, about 10-20% of the time, an individual experiencing an allergic reaction of this severity may need a second dose of epinephrine to relieve symptoms.

Food Allergy Symptoms in Children

It is important to recognize that children with food allergies may describe their symptoms differently than an adult would. Children may not know the right words to describe the symptoms you can more easily recognize.  Be aware that the child with food allergies may say something like “this is too spicy,” or “my tongue feels thick,” when they eat a trigger food. They may also become very fussy or irritable, experience stomach pain or diarrhea, and be unable to explain what they are experiencing.  

If your child starts to experience facial, mouth or tongue swelling or is experiencing trouble breathing, call 911 immediately. Do not wait for symptoms to subside or worsen to react, it is important to act quickly.   If you are concerned that your child may have food allergies or be at risk for food allergies, talk to your pediatrician about seeing a board-certified allergist. 

For these reasons, it is even more important to be aware of any potential food allergies in babies and toddlers.  The symptoms may different in babies with food allergies, and again as they can not communicate easily, it is the caregiver's responsibility to watch out for potential allergy symptoms. 

Edited by Marlo Mittler, MS RD 

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