Food Allergy

Is this your child's symptom?

  • Allergic reactions to foods
  • The most common symptom is hives
  • Questions about food allergies
  • Oral Allergy Syndrome is also covered. The main symptom is mouth itching and swelling. The main triggers are raw fruits and veggies.

Symptoms of Food Allergies

  • Hives all over and swelling of the face are the most common symptoms. Hives are raised pink bumps with pale centers (welts). They look like bug bites.
  • Mouth itching and swelling
  • Runny nose and coughing
  • Vomiting and diarrhea
  • Life-threatening allergic reactions also must have trouble breathing and/or swallowing. The medical name for this is anaphylaxis. Most of these reactions have a sudden onset within 10 to 20 minutes. All occur within 2 hours of eating a certain food. People who have had this carry an emergency kit like an Epi-Pen.

Causes of Food Allergies

  • 8 foods cause 90% of food allergies
  • In the first year of life: cow's milk, soy milk and egg
  • Older children: peanuts, tree nuts, fish, shellfish and wheat
  • Shellfish include shrimp, crab, lobster, clams, oysters and scallops
  • Tree nuts include all the nuts (such as almonds and cashews) except peanuts.
  • Of children with a proven food allergy, 40% have severe reactions. The other 60% have mild reactions.
  • Peanuts and tree nuts are the most common triggers for severe reactions.

Cross Reactions with Other Foods

Children with allergies listed below can react to other foods:

  • Cow's milk allergy: 90% also react with goat's milk and 40% with soy milk
  • Egg: 5% react with chicken
  • Peanut: 5% react with other legumes (like peas or beans). About 30% also react to tree nuts.
  • Tree nut: 40% react with other tree nuts
  • Fish: 50% react with other fish. Only 10% also react to shellfish.
  • Shellfish: 70% react with other shellfish
  • Melon: 90% react with banana and avocado

How Long do Food Allergies Last?

  • Cow's milk: 80% outgrown by age 16
  • Soy milk: 80% by age 16
  • Egg: 70% by age 16
  • Peanut: 20% by age 16
  • Tree nut: 10% by age 16

Allergic Disease - Can You Prevent with Diet?

  • Most allergic diseases (food allergies, eczema and asthma) cannot be prevented.
  • Helpful: Feeding only breastmilk for 6 months or longer
  • Not helpful: Avoiding high-risk foods for pregnant or breastfeeding women
  • Not helpful: Soy formulas instead of cow's milk formula
  • Not helpful: A delay in starting baby foods past 6 months
  • Not helpful: A delay in starting high-risk foods like peanut butter or eggs
  • Source: AAP

Oral Allergy Syndrome (OAS)

  • A minor reaction to some raw fruits and veggies
  • Causes itching and swelling only to the lips and tongue
  • Also called Pollen-Food Syndrome

Symptoms of OAS

  • Rapid onset of itching (or tingling) and swelling of the mouth.
  • This can involve the lips, tongue, throat, and roof of the mouth.
  • The uvula (tag of tissue hanging down in back) can become very swollen.
  • These symptoms follow eating a high-risk raw fruit or veggie.
  • OAS can start by age 5.
  • Serious symptoms or very bad reactions rarely happen.

Causes of OAS

  • A contact allergy. It only involves the parts of the mouth that touch the raw food.
  • Trigger foods for OAS are always raw (not cooked.)
  • Fresh Fruits. These include apple, apricot, banana, cherry, melons, orange, peach and pear.
  • Raw Veggies. These include carrot, celery, parsley, potato and tomato. Carrots and celery have the highest risk for also causing serious symptoms.
  • Certain Seeds. These include sunflower seeds and fennel seeds.

OAS and Nose Allergies Can Be Linked

  • Over 50% of people who are allergic to pollen also have OAS. This means 10% of all people.
  • Ragweed pollen allergy can cross-react with all melons. Also, sometimes with bananas and tomatoes.
  • Birch pollen allergy can cross-react with raw potatoes, carrots, celery and apples.
  • Grass pollen allergy can cross-react with tomato and kiwi.

When to Call for Food Allergy

Call 911 Now

  • Life-threatening allergic reaction to similar food in the past. Food eaten less than 2 hours ago.
  • Trouble breathing or wheezing
  • Hoarse voice or cough start all of a sudden
  • Trouble swallowing, drooling or slurred speech start all of a sudden
  • You think your child has a life-threatening emergency

Call Doctor or Seek Care Now

  • Hives all over start 2 to 4 hours after eating high-risk food. High-risk foods include nuts, fish, shellfish, or eggs.
  • Major face swelling (not just lips) starts 2 to 4 hours after eating high-risk food
  • Vomiting or stomach cramps starts 2 to 4 hours after eating high-risk food
  • Your child looks or acts very sick
  • You think your child needs to be seen, and the problem is urgent

Contact Doctor Within 24 Hours

  • Other symptoms that might be from a food allergy and present now
  • You think your child needs to be seen, but the problem is not urgent

Contact Doctor During Office Hours

  • Recurrent symptoms that might be from a food allergy but not present now
  • Oral Allergy Syndrome suspected but never confirmed by a doctor
  • Food allergy diagnosed and you want to restart that food
  • You have other questions or concerns

Self Care at Home

  • Food allergy: mild reaction
  • Oral allergy syndrome

Seattle Children's Urgent Care Locations

If your child’s illness or injury is life-threatening, call 911.

Care Advice

Treatment of a Food Allergy

  1. What You Should Know About Food Allergies:
    • About 5% of children have food allergies.
    • Most children with a new food reaction need to be seen.
    • If your child is stable, hives often can be treated at home.
    • Hives as the only symptom can have many causes.
    • Your child can be seen later to decide future risks and best treatment.
    • Here is some care advice that should help.
  2. Allergy Medicine for Hives:
    • Give Benadryl 4 times per day for hives all over. Age limit: 1 and older.
    • Use the allergy medicine until the hives are gone for 12 hours.
    • If the hives last more than a few days, switch to a long-acting antihistamine, such as Zyrtec. No prescription is needed. Age limit: 2 and older.
    • Caution: if your child is less than 1 year, call your doctor for advice.
  3. Cool Bath for Itching:
    • To help with any itching, can also give a cool bath. Do this for 10 minutes.
    • Caution: Do not cause a chill.
  4. How to Prevent Future Reactions:
    • Help your child avoid the food that caused the symptoms.
    • Read labels on all food products fully.
    • Tell other people who care for your child of your child's food allergy. Also, inform the staff at your child's school.
    • Learn more at Food Allergy Research and Education.
  5. What to Expect:
    • Hives from foods often last just a short time.
    • They often are gone in less than 6 hours.
  6. Return to School:
    • Hives cannot be spread to others.
    • Your child can go back to school once feeling better. The hives shouldn't keep him from doing normal things.
  7. Call Your Doctor If:
    • Trouble breathing occurs
    • Trouble swallowing or drooling occurs
    • Severe hives not better after 2 doses of Benadryl
    • Hives last over 24 hours
    • You think your child needs to be seen
    • Your child becomes worse

Treatment of Oral Allergy Syndrome Symptoms

  1. What You Should Know:
    • Oral Allergy Syndrome (OAS) is very common. It happens in 10% of people. Most of them also have pollen allergies.
    • The symptoms are not harmful and can be treated at home.
    • Needed for OAS: Your child has never had any serious symptoms with this food.
    • OAS symptoms don't last very long.
    • Here is some care advice that should help.
  2. Rinse the Mouth:
    • Rinse the lips and mouth with warm water. Do this a few times.
    • Reason: To remove any traces of the food.
  3. Cold Pack:
    • Use ice or a cold pack to the swollen lips or tongue for 10 minutes.
    • Reason: To lessen the swelling and the itch.
  4. Allergy Medicine:
    • One dose of Benadryl may help the symptoms go away faster.
    • No prescription is needed. Age limit: 1 or older.
  5. How to Prevent Future OAS:
    • Keep a list of the foods that cause your child's symptoms.
    • Avoid these foods if they are raw (fresh).
    • The cooked version of these foods usually won't cause any symptoms.
  6. What to Expect:
    • With or without treatment, the itching will go away in 1 to 2 hours.
    • The mouth swelling will also go away quickly.
  7. Call Your Doctor If:
    • Trouble swallowing or drooling occurs
    • Trouble breathing occurs
    • Swelling or rash occurs anywhere else
    • You think your child needs to be seen
    • Your child becomes worse

And remember, contact your doctor if your child develops any of the 'Call Your Doctor' symptoms.

Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.

Last Reviewed: 10/11/2023

Last Revised: 12/30/2022

Copyright 2000-2023. Schmitt Pediatric Guidelines LLC.