Food Allergy Symptoms

How to recognize the signs of an allergic reaction to food

Food Allergy Symptoms
Anaphylaxis can happen in minutes.. (c) A.D.A.M.

You ate Aunt Bev’s potato salad, and now you feel awful. Are you experiencing an allergic reaction, or was the salad left out in the sun too long? Some of the symptoms of food allergies are similar to food poisoning, others may be confused with asthma or pollen allergies. It is important to work in partnership with your doctor to figure out what is causing your symptoms. It can take time and detective work to figure out if your symptoms are being caused by food or if there is another underlying cause.

Symptoms of a classic (Ig-E mediated) food allergy usually begin within two hours of eating a trigger food. Symptoms of food sensitivities, such as lactose intolerance or an auto-immune disorder such as celiac disease, may be delayed up to 12 hours. And yet, some food allergies impact daily life and are difficult to pinpoint to food.

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

Your doctor may suggest treating skin reactions with an oral antihistamine, such as Benadryl (diphenhydramine) or topical agents like steroid creams, calamine lotion, or oatmeal baths.

Many hives all over your body or swelling all over your body are serious conditions in need of emergency medical care.

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

A chronic stomachache may be a sign that you have a food allergy, or it may be a sign that you have lactose intolerance, celiac disease, inflammatory bowel disease (IBD), or something else. Antihistamines do not help these syndromes.

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


Food allergies can affect the lungs, 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.

  • 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

Your doctor may suggest that mild swelling or rash on lips or tongue be treated with an oral antihistamine, such as Benadryl.

Swelling of the airways to the point where you have trouble breathing, have a short, barking cough, or have trouble swallowing is a sign of anaphylaxis and requires emergency treatment.


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

  • Redness
  • Itching
  • Watering
  • Swelling

Your doctor may suggest treating itchy, watery eyes with an oral antihistamine.

Severe, Full-Body Reactions (Anaphylaxis)

Anaphylaxis is a type of shock (loss of blood pressure) caused by an allergic reaction. It usually begins within two hours of eating an allergen, and often begins within minutes. It may involve any of the above symptoms, or combination of the above, plus any of the following:

  • Sense of impending doom
  • Difficulty breathing
  • Pale skin
  • Dizziness, lightheadedness: This is typically due to low blood pressure
  • Loss of consciousness: Low blood pressure, decreased heart rate

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 beginning 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 (10-20% of the time) an individual experiencing an allergic reaction will need a second dose of epinephrine to relieve symptoms.

Food Allergy Symptoms in Children

Children may describe their symptoms differently than an adult would. Your child might say something like “this is too spicy,” or “my tongue feels thick,” when they eat a trigger food. Children may become very fussy or irritable and be unable to explain what they are experiencing.

If your child's face, mouth, or tongue is swelling, or he is experiencing trouble breathing, call 911. 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.

Symptoms may also be different in babies with food allergies.

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