Illness & Symptoms
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
 Call Doctor or Seek Care Now
  |  
  Contact Doctor Within 24 Hours
 Contact Doctor During Office Hours
  |  
  Self Care at Home
  |  
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
 
Care Advice
Treatment of a Food Allergy
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.
 
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: 6 months and older.
 - Zyrtec dosing for 6 months to 2 years: 2.5 mL (2.5 mg) every 24 hours.
 - Zyrtec dosing for 2 years and older: follow package directions.
 
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.
 
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.
 
What to Expect:
- Hives from foods often last just a short time.
 - They often are gone in less than 6 hours.
 
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.
 
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
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.
 
Rinse the Mouth:
- Rinse the lips and mouth with warm water. Do this a few times.
 - Reason: to remove any traces of the food.
 
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.
 
Allergy Medicine:
- One dose of Benadryl may help the symptoms go away faster.
 - No prescription is needed. Age limit: 1 or older.
 
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.
 
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.
 
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
 
Remember! Contact your doctor if you or your child develop any "Contact 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.
Copyright 2000-2025 Schmitt Pediatric Guidelines LLC.
Reviewed: 5/5/2025 Updated: 1/25/2025

