Infographic with asthma facts
What you need to know about

Food allergies

What are food allergies?

  • Abnormal immune responses to specific food allergens, substances that cause your immune system to overreact and treat them like they’re dangerous to your health
  • Triggered mostly by proteins

Common food allergens

The following allergens cause 90% of food allergy reactions:

  • Cow’s milk
  • Eggs
  • Peanuts
  • Tree nuts
  • Fish
  • Shellfish
  • Soy
  • Wheat


  • Highest food allergy rates are found in children under age 5.
  • Children with this condition are two to four times more likely to have asthma or other allergies.
  • Most children with cow’s milk allergy develop it before age 1, but 80% can physically tolerate cow’s milk by age 5.
  • More than one-third of children with atopic dermatitis have food allergies.
  • About 6-8% of children with asthma have food-induced wheezing.
  • Only 2% of adults have food allergies.
  • Peanuts, fish, shellfish and tree nuts are responsible for 85% of adult food allergies.

Risk factors

  • Family history of asthma and allergies, especially peanut allergies
  • Under 3 years old
  • Test results showing high levels of allergen-specific antibodies

Signs and symptoms

Food allergy symptoms, which can be sudden and severe but may be delayed up to two hours after ingesting allergens, include:

  • Hives or swelling
  • Tingling in mouth
  • Swelling of tongue and throat
  • Difficulty breathing
  • Abdominal cramps
  • Vomiting or diarrhea
  • Eczema, rash
  • Coughing or wheezing
  • Loss of consciousness
  • Dizziness
  • Anaphylaxis – the most severe symptom, often occurring in seconds or minutes after ingestion of offending food even if it is cooked

Symptoms occurring more than two to three hours after ingestion or hives that persist for days or weeks without re-exposure to the suspected food allergen are unlikely to be food allergy-related.

Diagnosis and testing

Allergist performs thorough medical history and physical examination. If history suggests immune reaction to any foods, allergy skin testing is conducted.

How it works:

  • Small samples of food extracts are applied to the skin with no needles involved.
  • Results are read in 20 minutes.
  • Hives mean positive results for food allergies.

Allergists may also conduct an immune cap test, a blood test that measures antibody levels for specific foods, or food challenges. This involves giving small doses of foods in gradually increasing amounts while monitoring vital signs, skin, mucosa and lungs for reaction. Food challenges are performed in medical settings with emergency equipment available.


  • Food allergen avoidance – Strict dietary avoidance is the only proven way to avoid reactions. Breastfeeding mothers must strictly avoid the offending foods also.
  • Food label monitoring – Labels must note in plain English which foods contain ingredients derived from milk, egg, soy, wheat, peanut, tree nuts, fish and shellfish.
  • Allergy education through Food Allergy and Anaphylaxis Network (FAAN). Read more here.
  • Antihistamine use – Only for symptoms involving skin reactions
  • Emergency action plan – Children, parents and school faculty should have plans for managing food allergies at home and school, include use of an epinephrine injector (Epi-Pen):
    • Epinephrine administration is the treatment of choice for anaphylaxis.
    • It should be followed by transport to closest hospital for evaluation, treatment, observation and monitoring of potential second-phase allergic reactions.
  • Food SLIT – We offer sublingual immunotherapy for certain foods to help protect against serious life-threatening reactions from accidental exposure to offending foods. (Read more about Food SLIT here)

Prevention of food allergies in children

For infants at higher risk of developing allergies because at least one parent or sibling has documented allergic disease, exclusive breastfeeding for at least four months decreases risk of developing cow’s milk allergy through age 18 months.

  • Newer American Academy of Pediatrician recommendations say pregnant women need not avoid peanuts or other highly allergenic foods during pregnancy unless they themselves are allergic to them.
  • Solid foods shouldn’t be introduced before age 4 months. After this age, there is no need to restrict allergic foods from infants’ diets.

Chances of food allergy resolution

Studies show that:

  • 79% of children with cow milk allergy resolve by age 16
  • 68% of children with egg allergy resolve by age 16
  • Only 20% of young children develop a tolerance to peanuts
  • Less than 10% outgrow tree nut allergies

Non-allergic food related conditions

  • Food intolerance/adverse reaction – Abnormal response to foods or food additives that doesn’t involve the immune system. An example is lactose intolerance, where patients who lack enzymes needed to break down milk sugars for proper digestion experience abdominal bloating and discomfort.
  • Oral allergy syndrome – A form of urticaria (hives) where contact with certain plant proteins that react with airborne allergens causes itching/swelling of lips, tongue, palate or throat. Symptoms often occur after ingesting fruits and vegetables and usually resolve quickly. Patients with allergic rhinitis caused by ragweed may develop symptoms after eating watermelon, cantaloupe, honeydew or bananas. Patients sensitive to birch tree pollen may develop symptoms after eating raw potatoes, carrots, celery, apples or hazelnuts.
  • Exercise-induced food-associated anaphylaxis – Severe allergic reaction occurring only when patient exercises within a few hours of ingesting offending food, which doesn’t provoke the reaction without exercise. Most common in females ages 15-35 and diagnosed through patient history and food-specific test results.